A Le Pape

C Lienard

C Verbeke

M Pruvost

J.-L De Coninck

Helicopter Fuselage Drag Reduction Using Active Flow Control: A Comprehensive Experimental Investigation

T pulsed jet period, s V jet jet exit peak velocity, m/s V ∞ freestream velocity, m/s VR blowing rate or velocity ratio, V jet /V ∞ W fuselage width = 0.244 m w flow control slot width, m α angle of attack, • ρ ∞ freestream density, kg/m 3 ρ jet jet density, kg/m 3

A comprehensive experimental investigation of helicopter blunt fuselage drag reduction using active flow control is being carried out within the Clean Sky project. The objective is to demonstrate the capability of several active technologies to decrease fuselage drag by alleviating the flow separation occurring in the backdoor area of some helicopters (with pronounced ramp for backdoor loading). The work is performed on a simplified blunt fuselage at model scale. Several active flow control actuators are considered for evaluation: steady blowing, unsteady blowing (or pulsed jets), and zero-net-mass-flux blowing (or synthetic jets). Laboratory tests of each individual actuator are first performed to assess their performance and properties. The fuselage model is then equipped with these actuators distributed in eight slots forming a U-shape on the fuselage backdoor. This paper addresses the promising results obtained during the wind tunnel campaign, since significant drag reductions are achieved for a wide range of fuselage angles of attack. Moreover, a flow control strategy depending on the fuselage attitude is proposed. The link between the best actuation scheme for this attitude and the corresponding flow topology of the backdoor separation is also discussed.

q freestream dynamic pressure = 1/2ρ ∞ V 2 ∞ ,Pa

Introduction

The reduction of helicopter parasite drag has become a significant issue as emphasis is put on speed achievement and on minimizing the impact of the growth of rotorcraft traffic on the environment. Helicopter's primary source of drag is bluff body drag (pressure drag) from pylon/hub/fuselage/landing gear flow separation and interference. Fuselage drag is mainly due to the massive flow separation that occurs on the rear of the fuselage, especially for helicopters with a very pronounced aft loading ramp. This separation results in a large amount of pressure drag, but can also induce an unsteady wake in the tail boom vicinity. On nonrotating or nonlifting parts, the variety of helicopter missions fits well with active devices that can be activated on-demand and separation alleviation through active flow control is an attractive solution to reduce rotorcraft drag. Separation control effectiveness has indeed been successfully demonstrated using active actuators for a wide range of aerospace applications (Refs. 1 and 2) using numerous types of actuators (Ref. [START_REF] Cattafesta | Actuators for Active Flow Control[END_REF]) and is currently a very active area of research in aerodynamics. Several applications for rotorcraft configurations have been published, in general for drag reduction purposes. For example, flow control has been applied to hub fairing or hub pylon separation control (Refs. [START_REF] Arad | Control of Massive Separation on a Thick-airfoil Wing: A Computational and Experimental Study[END_REF][START_REF] Wilson | Turbulence Measurements on a 2D NACA0036 with Synthetic Jet Flow Control[END_REF][START_REF] Potsdam | CFD Investigations on a NACA0036 Airfoil with Active Flow Control[END_REF] showing the capability of active blowing to alleviate flow separation on a thick airfoil. Several authors demonstrated that fuselage drag reduction could be achieved using various types of actuators such as vortex generators (Ref. 7), steady blowing (Refs. 8, 9), synthetic jets (Refs. 8-10), combustion actuators (Ref. 11), or plasma actuators used as vortex generators (Ref. 12). All these studies demonstrate fuselage drag reduction of about 15% depending on the configuration, the type of actuation and the flow condition. These drag reduction assessments are supported mainly by wind tunnel tests on simplified configurations and also by numerical simulations for the simplest actuations (Refs. 7-10). However, most authors usually focus on a specific configuration along with a specific actuator, thus making it difficult to compare the different actuation systems. The objective of this paper is to present a wind tunnel test demonstration of efficient flow control on a simplified helicopter blunt fuselage for drag reduction. This investigation has the distinctive feature of comparing several steady and unsteady actuators in the same experiment on the same helicopter fuselage. Furthermore, these experimental results are not restricted to a single fuselage attitude but cover a wide range of angles of attack, hence demonstrating the capability of active flow control to reduce fuselage drag for various flight conditions corresponding to different fuselage attitudes. Previous work on the same simplified configuration revealed that two main flow topologies could occur on the fuselage depending on its incidence (Ref. 9). The present work also aims to show what kind of active flow control strategy is the most suitable for each flow topology.

The paper first presents the simplified helicopter model and the wind tunnel test setup. A second part is dedicated to the presentation of the different actuators and their property and performance evaluation during specific preliminary laboratory tests. Wind tunnel tests measurements that include aerodynamic loads acting on the fuselage, static pressure taps, unsteady pressure, and particle image velocimetry (PIV) measurements are presented and discussed. An overall analysis of the results including actuators comparison with respect to achieved drag reduction is then presented. The paper finally discusses the choice of the most suitable control strategy depending on the blunt fuselage angle of attack.

Wind Tunnel Tests

ASF2 simplified fuselage configuration

The current research effort applies on a generic fuselage, the ASF2 (Fig. 1), based on a fully open geometry. Already studied around 1985-1990 at ONERA (Ref. [START_REF] Gleyzes | Experimental and Numerical Study of the Flow around an Helicopter Fuselage. Determination of Drag Coefficient[END_REF], this fuselage has a pronounced ramp to produce a large separation. The particularity of this fuselage is the rounded shape of its ramp or backdoor area that leads to a strong three-dimensional separation. Separation location is not directly set by the geometry and can change depending on the fuselage angle of attack (Ref. 9). In addition, similarly to observations reported by Seddon in Ref. 14, two flow topologies have been identified numerically and experimentally (Ref. 9) for positive and negative angles of attack, respectively. It can be added that this simplified fuselage had originally been designed so that the laminar/turbulent transition occurred slightly downstream of its nose at the maximum curvature location. Tripped transition cases and natural free transition cases have been compared in the current experiment, demonstrating a marginal influence of the transition. Consequently, all the experimental results presented in this paper are for a natural free transition.

Experimental setup

The wind tunnel tests were conducted in the ONERA L1 wind tunnel in Lille, France. This research facility is an Eiffel-type wind tunnel with a return hall, which can reach wind speeds up to 75 m/s and has a circular test section with a diameter of 2.4 m. The model is approximately 1 m long and is mounted upside down on two struts in the test section. When not specified, the freestream velocity is 40 m/s, corresponding to a Reynolds number based on fuselage length of approximately 2.9 million (0.65 million if based on fuselage width). The freestream turbulence intensity of the wind tunnel is estimated to be equal to 0.3%. The blockage ratio is 1.5%; therefore, wall effects on the model should be negligible.

An external balance (Monnin type) is used to measure drag, lift, and pitching moment to ensure the highest drag measurements accuracy. The Monnin balance principle is based on balancing the main part of the force by marked masses acting as counterweights, while determining the residual part by measuring the deformation of flexion plates. This principle makes it possible to have a constant sensitivity of 10 g regardless of the load. This sensitivity corresponds to less than 1% of the fuselage and strut minimum drag value for V ∞ = 40 m/s (achieved at α = 0 • ). The struts loads are then measured and subtracted to determine the isolated fuselage drag. For flow control cases, the additional forces due to the jets blowing and in particular the generated thrust are measured by performing a run without wind for all angles of attack. The measured thrust is then subtracted to compare isolated fuselage drag of all cases. The thrust values have been found to be much smaller than the drag measurements (∼1 to 2% of the drag value, depending on the blowing coefficient).

Model instrumentation and measurements

The ASF2 model is instrumented with 87 pressure taps located in the symmetry plane, on the meridian lines on both sides of the fuselage, and in the ramp region. Ten Kulite R unsteady pressure transducers are added on the ramp and on the tail boom (Fig. 2). Unsteady pressures are acquired at a sampling rate of 1280 Hz for 10 s (parametric study) or 45 s (selected cases of interest).

Actuator integration

The simplified blunt fuselage model was designed so that eight removable actuators could be added in the backdoor region in a U-shape arrangement (Fig. 3). This arrangement, as well as slot length, width, and blowing angle, has been determined based on numerical investigations presented in Ref. 9. A modular design of the model backdoor region allows several types of actuators to be tested in the same model during the same experiment. Presently, three types of slotted actuators are considered:

1) Steady blowing: An air supply external to the model allows several flow rates and blowing velocities to be tested.

2) Pulsed jets or unsteady blowing: Using the same actuator, blowing can be turned on and off at various frequencies and duty cycles.

3) Synthetic jets or zero-net-mass-flux (ZNMF) blowing: A different actuator is used to produce periodic suction and blowing, for various frequencies and blowing velocities, without the need of an external air supply.

Actuators have been designed and manufactured at ONERA (see Ref. 15 for further information) to meet performance specifications based on a literature review and on computational fluid dynamics (CFD) computations (Ref. 9). Final slot length is 30 mm, slot width is 0.67 mm, and slot angle with respect to the local surface is 45 • .

Actuator Laboratory Tests

Objective and experimental process

An essential phase in the test preparation is the extensive laboratory test of each individual actuator (Fig. 4). Each actuator is individually qualified on a dedicated bench. The first objective is to confirm that its properties match the technical specifications. This phase also aims to ensure the homogeneity of all the actuators, since eight of them can be used simultaneously on the model during the wind tunnel test. Finally, the laboratory tests are also used to perform fine measurements of the actuators performance (e.g., input voltage response, input frequency signal response) that are crucial information for control of the actuators during the wind tunnel tests. This information is mandatory since a simple monitoring of the actuators is performed during the wind tunnel test, without any actuator performance measurements.

To perform these measurements, a dedicated test bench in still air conditions has been developed at the ONERA Lille facility. Measurements are performed using a hot wire whose position relative to the actuator slot exhaust can be accurately adjusted. To acquire reliable and accurate results, particular attention is paid to the hot-wire calibration procedure. A specific procedure has been developed (Ref. [START_REF] Ternoy | Overview of ONERA Actuators for Active Flow Control[END_REF]) to take into account the fact that the size of the hot wire and the jet slot are of the same order. In such a case, the hot-wire active sensor is not uniformly cooled, due to the jet velocity profile. This actuator qualification bench and the

Sample bench test results

Hot-wire measurements during actuator bench tests include peak velocity evaluation, slot span, and width velocity distribution measurements, as well as input signal voltage and frequency response. For each slot geometry, measurements were repeated for each type of actuation (steady blowing, unsteady blowing, and synthetic jets). Figure 5 presents, for example, the measured velocity peak of the eight synthetic jet actuators for varying voltage inputs for a given actuation frequency of 185 Hz. A linear response of the jet peak velocity in the blowing phase is obtained with respect to input voltage. A generally good homogeneity is observed between the actuators with a maximum peak velocity approximately equal to 100 m/s for the maximum input voltage. Actuator 2 shows slightly better performance (10% higher), but this discrepancy is considered acceptable. Figure 6 presents an example of velocity measurements along the slot length showing a good homogeneity of the velocity distribution in this direction.

An example of time measurements for a given synthetic jet actuator is given in Fig. 7. Measurements have been acquired over three periods. The hot-wire measures the jet velocity in the blowing phase (the blowing phase is not locked at a specific t/T in this measurement example) but cannot provide reliable information in the suction phase (hot wire is positioned approximately 1 mm above the jet in order not to affect the peak velocity).

Such time measurements are then used to determine the momentum coefficient or blowing coefficient C µ used in active flow control field to estimate actuation authority. The blowing coefficient is defined as Based on the synthetic jet blowing phase measurements, a simple model is built. A semi-sine wave function is chosen to fit the blowing phase measurements. It should be noted that the blowing duration is not necessarily half the period: The measurements reveal that the blowing phase can be shorter depending on frequency actuation and voltage input. The suction phase is then deduced and modeled by another semi-sine that exactly compensates the blowing flow rate by considering the ZNMF assumption. An example of this semi-sine reconstruction of the blowing and suction phases is illustrated in Fig. 8. Afterward, this information is used to calculate the blowing coefficient C µ (integration of V 2 jet (t)). In the present paper, the blowing coefficient C µ is given for all the activated jets (eight or four activated slots using averaged peak velocity measurements of each individual actuator) of the considered configuration for a fair comparison of the flow control authority depending on the chosen flow control scheme. The peak velocity measurement is used for the synthetic jet when the measured mass flow is used for the steady blowing and pulsed jet for the blowing coefficient calculation.

C µ = n jet ρ jet A jet V 2 jet (t) t 1 2 ρ ∞ A CS V 2 ∞

Bench test conclusions

A detailed analysis of the actuator laboratory test data has been performed, and a summary of the main results and observations is presented below:

1) An acceptable homogeneity is observed between the eight actuators of each type in terms of peak velocity, frequency response, and input voltage response.

2) An evaluation of velocity distribution profiles for slot width and length (not presented) has been performed, showing a constant blowing velocity along the slot length for all actuator types.

3) Actuator bench tests assessed the performance of each actuator. The results are also used to choose the proper input parameters to prepare the wind tunnel test matrix and to control the actuators during the wind tunnel test. In particular for each actuator type, a) Steady blowing: mass flow rate to obtain the desired output peak velocity and momentum coefficient; b) Unsteady blowing: mass flow rate (output peak velocity and momentum coefficient), achievable frequency range, and minimum dutycycle achievable; and c) Synthetic jets: input voltage, actuation frequency, and input signal shape to obtain the desired output peak velocity and momentum coefficient.

Results and Discussion

Test matrix

Measurements have been performed for several wind speeds, but most flow control cases are for a freestream velocity of 40 m/s. Each case comprises a complete fuselage polar from -10 • (nose-down) to 6 • (nose-up) with approximately 20 different angles of attack within this range. Combined with all jet input parameter permutations, a large parametric study was achieved. The considered flow control cases are detailed below:

1) Steady blowing:VR= V jet /V ∞ from 1 to 3 for eight slots, various four-slot configurations (side slots only, bottom slots only, every other slot).

2) Unsteady blowing:V R= V jet /V ∞ from 1 to 3 for eight slots, various four-slot configurations (side slots only, bottom slots only, every 3) Synthetic jets:VR= V jet /V ∞ from 1 to 2.6, eight-slot and four-slot configurations, frequency sweep from 50 to 200 Hz, slot phasing scheme influence, input signal shape influence.

A total of approximately 150 fuselage polars were acquired and are used in the present paper in the following results description and analysis.

Baseline results

Baseline cases are performed with either blanks installed instead of the actuators slots or with the slots without blowing. The influence of the slots on the baseline results is found to be negligible, and the drag and lift measurements presented in Fig. 9 are the average of all repeated cases (∼20 runs) performed during the wind tunnel test. Error bars indicate the standard deviation of the measurements and illustrate the overall measurement repeatability and accuracy, which is estimated at ±1.25% of the averaged value for the drag.

The drag and lift curves exhibit two main parts that have been associated with two different flow topologies as detailed in Ref. 9 and summarized as [START_REF] Gad-El Hak | Flow Control: Passive, Active, and Reactive Flow Management[END_REF] an "eddy flow" topology for nose-up angle of attack (α>-2 • ), for which the flow is a classical bluff-body flow consisting of cross-stream eddies, and (2) a "vortex flow" topology for nose-down angle of attack (α<-2 • ), for which the flow is characterized by streamwise vortices.

Steady blowing results

First flow control results are presented for steady blowing using the eight slots and for increasing blowing rate values VR = V jet /V ∞ from 1 to 3 (Fig. 10). Corresponding blowing coefficients C µ are indicated in the legend. For VR = 1, the influence on the fuselage drag is very limited with a slight drag reduction observed in the vortex flow region for α =-2.5 • . Significant drag reduction can, however, be observed for VR = 1.5 with 10-15% drag reduction for negative fuselage angles of attack (α<-2 • ). For fuselage angles of attack from α =-2 • to 2 • ,a drag increase is observed and a drag reduction of approximately 10% is then obtained for nose-up angles of attack. The fuselage drag polar for VR = 1.5 is smoother than the baseline one with a shallow evolution of the drag. The lift polar (Fig. 11) shows the same feature with a smooth Increasing the blowing coefficient C µ and velocity ratio shows the same trends as for VR = 1.5. Drag reduction is more significant for negative angles of attack, whereas the drag increase around 0 • angle of attack is accentuated. Pressure distributions on the backdoor ramp region of the fuselage are plotted in Fig. 12 for a fuselage angle of attack equal to -5 • . Drag reduction is obtained by a base pressure increase on the backdoor region of the helicopter fuselage. Higher drag reduction and backdoor pressure rise are observed for increased jet velocity ratios and momentum coefficients. For the highest blowing coefficient corresponding to VR = 3, a drag reduction of 23.7% is obtained.

The evolution of the measured drag reduction with the momentum coefficient C µ shows that the fuselage drag value reaches a plateau for high blowing rates (Fig. 13). For a momentum coefficient C µ equal to 1.85% (VR = 2), a drag reduction of 21.8% is obtained and a drag reduction of 23.6% is obtained for C µ equal to 4.35%. Figure 13 also presents the drag reduction obtained for other control schemes: using only the four bottom slots (blue circles) leads to similar drag reduction as the eight-slot case. However, using the four side slots (purple triangles) allows much higher drag reduction at a given momentum coefficient. A maximum drag reduction of 32% is thus obtained for the four side slots active with a C µ = 0.93%.

Pulsed jets or unsteady blowing results

Investigation of pulsed jet effectiveness begins with the idea of saving half the supplied mass flow through the use of a duty cycle DC equal to 50%. First, the mass flow rate is adjusted to equal the mass flow rate for a steady blowing case with a velocity ratio VR = 1.5. Then the unsteady actuation is adjusted to obtain the desired duty cycle. The influence of the actuation frequency f is first evaluated and presented in Fig. 14 for a fuselage angle of attack equal to -5 • . One can notice a limited frequency effect in the investigated range. Drag reductions around 10-15% are obtained for frequencies up to f = 165 Hz, whereas those reductions are more limited for f = 200 Hz. Actuator limitations constrained the actuator frequencies to a maximum of 200 Hz, so no information is available for higher frequency actuations. Unsteady actuation seems to lead to slightly higher drag reductions than the corresponding steady blowing case. In particular, the highest drag reduction is obtained for f = 82 Hz, corresponding to a reduced frequency, based on fuselage width W ,o f f + ∼ 0.5. This value is close to the value identified by Schaeffler et al. (Ref. 8) for ZNMF blowing actuation in their computations.

The influence of the duty cycle has been evaluated for an actuation frequency f = 82 Hz (f + = 0.5). The objective is to minimize the duty cycle and therefore the momentum coefficient, while keeping similar drag reductions. Pressure distributions and obtained drag reductions for varying duty cycles from 25% to 100% (steady blowing) are compared in Fig. 15 for a fuselage angle of attack α =-5 • .ForDC= 75%, a slightly better drag reduction is observed in comparison to the steady blowing case (15.41% instead of 12.33%). Improvement of the drag reduction is achieved through an increase of the base pressure on the ramp region of the helicopter fuselage similarly to what is observed for steady blowing cases (Fig. 12). For DC = 50%, the drag reduction is the same as the one obtained for DC = 75%. For DC = 25%, the drag is reduced by

Synthetic jet results

Experimental results of a drag reduction study obtained with ZNMF blowing or synthetic jets are presented in this section. No significant frequency effect could be identified. The results are presented as a function of the velocity ratio VR and the blowing coefficient C µ , which are calculated using laboratory test results. Several slot configurations for a given velocity ratio of 2 are compared in Fig. 16. No drag reduction is observed for the eight-slot configuration: For negative angle of attack (α<-3 • ), drag is unchanged compared to the reference case; for higher angles of attack, drag increases. Only four-slot configurations seem to lead to drag reductions:

1) For negative angles of attack, the four-side-slot configuration allows drag to be reduced for a limited range of fuselage angles of attack (around α =-2.5 • ) with a maximum drag reduction of approximately 15%.

2) For positive angles of attack (α>2.5 • ), the four-bottom-slot configuration is the most effective with a maximum drag reduction of 10%.

The influence of the slot actuation scheme is presented in Fig. 17 for a negative angle of attack ("vortex flow" topology for the reference case). This plot gathers the results obtained for each synthetic jet test case performed during the wind tunnel parametric study. The figure emphasizes that, at this angle of attack, eight-slot and four-bottom-slot configurations lead to drag increases for all momentum coefficients tested. Only the four-side-slot configuration induces drag reductions for momentum coefficients higher than 0.2%. This observation is all the more interesting when compared to the same results for a positive angle attack ("eddy flow" topology for the reference case) as plotted in Fig. 18. Here the four- side-slot configuration leads to a drag increase, even at high momentum coefficients. The trend is completely reversed in comparison with the "vortex flow" case: the higher the momentum coefficient, the higher the drag increase. The eight-slot configuration is also ineffective at reducing the fuselage drag. In this case, the four-bottom-slot scheme is the only one to achieve drag reductions (for momentum coefficients higher than 0.2%). These observations highlight that the control scheme should depend on the flow topology (and therefore on the angle of attack) to obtain drag reductions for sufficient momentum coefficients. This correlation between the slot configuration and the original flow topology qualitatively makes sense. Indeed, the vortex flow is characterized by large streamwise vortices emitted in the tail/body junction area, close to the side slots. Conversely, the eddy flow topology consists of cross-stream eddies, generated by the flow separation and growth in the separation shear layer, which can be more easily affected by the bottom slots. A drag increase is observed in all cases at very low blowing coefficients, showing an influence of the jets at a very small control authority. This drag increase has been correlated with pressure measurement differences in the ramp area and is not due to any measurement uncertainties.

Pressure distributions obtained with a four-side synthetic jet configuration for a negative angle of attack and a four-bottom synthetic jet scheme for a positive angle of attack are, respectively, plotted in Figs. 19 and 20. For each case, the drag reduction (-17.3% for the negative angle of attack case and -8.4% for the positive angle of attack case) is obtained thanks to a base pressure increase on the fuselage backdoor region. For the positive angle of attack case, the pressure increase is higher but is balanced by a strong suction region at the beginning of the ramp due to flow acceleration by the bottom synthetic jet actuation.

Actuator comparison

Results obtained with the three different types of actuators and discussed in the above sections are compared. The chosen scaling parameter is the momentum coefficient or blowing coefficient C µ that is calculated based on actuator bench test measurements. Figure 21 presents the drag variations measured for all three actuation types using eight active slots. The obtained drag reductions follow a similar trend as a function of increasing blowing coefficient, independent of the actuation type employed. There is, for example, a good continuity between synthetic jet and steady blowing results. However, synthetic jets results are mainly clustered around low C µ values whereas steady blowing results extend over the whole investigated blowing coefficient range. This large range illustrates the much higher control authority that can be achieved with steady blowing but at the cost of additional air supply compared to a synthetic jet actuation system. Results in Fig. 21 demonstrate again the steady blowing saturation effect for high C µ values (discussed in Figs. 12 and13). The results obtained with pulsed jets are also in reasonable agreement with other actuator results, although more scattered because of the frequency effect discussed in the preceding section (see Fig. 14 results corresponding to C µ = 0.5%).

These results show that actuator authority can be compared based on blowing coefficient (possibly thanks to an identical slot layout and geometry for the three actuation systems).

Vortex flow control

Synthetic jet data revealed that, for negative angles of attack, corresponding to the "vortex flow" topology, drag reductions were limited to the four-side-slot configuration (Fig. 17). Steady blowing results also proved to be sensitive to the activated slot configuration (Fig. 13). Since actuators can be compared based on momentum coefficient, the objective of this section is to compare all actuation types for different slot configurations for the vortex flow case (negative angle of attack or nose-down fuselage). Figures 22 and23 present the results for the four-side-slot and the four-bottom-slot configurations, respectively, for α =-2.5 • . The four-side-slot control scheme (Fig. 22) induces significant drag reductions for all actuation types, with approximately 20% drag reduction for C µ values around 0.3%. Conversely, the results for the four-bottomslot configuration (Fig. 23) show drag increases for all actuation types and blowing coefficient values. This drag rise is partly due to a higher suction peak at the bottom of the backdoor region due to flow acceleration at the actuator exit, similar to the observation in Fig. 19. These results finally demonstrate that the primary parameter to achieve drag reduction is the activated slot configuration. For negative angles of attack for which the baseline flow is characterized by a vortex flow topology, only the four-side-slot configuration is able to produce significant drag reductions.

Eddy flow control

Similar analysis is conducted for positive angles of attack (nose-up fuselage), the "eddy flow" baseline topology. Figures 24 and25 present the drag reduction results at a fuselage angle of attack of 3.5 • for all three actuation types applied for the four-side-slot and the four-bottom-slot configurations. Here, activating the four side slots (Fig. 24) leads to large drag increases (∼5-10%) for all actuation types and no drag reduction is observed, even for high blowing coefficient values. Conversely, the four-bottom-slot configuration allows significant drag reductions to be obtained for all actuation types (Fig. 25). A maximum drag reduction of 10-12% is obtained for C µ values around 0.4%. Finally, the drag is increased for both slot schemes for high C µ values.

This drag increase for high momentum coefficients is due to the balance between the increase of the backdoor pressure and the increase of the suction peak at the beginning of the ramp as illustrated in Fig. 26. For C µ = 0.5%, the pressure is increased on the backdoor and a drag reduction of 11.6% is obtained. The suction peak is also increased at the bottom of the backdoor where the jets are blowing but the pressure drop is balanced by the pressure increase below the tail. For higher momentum coefficient, C µ = 0.9%, the suction peak is increased again and this time the pressure increase under the tail boom is not sufficient to balance the negative pressure due to the suction peak and the fuselage drag is increased by 2.3%. Therefore, a compromise has to be reached between increasing the base pressure at the center of the ramp without creating a large suction area at the beginning of the backdoor (due to bottom slots). This insight was already numerically identified and discussed by

Overall results synthesis

The previous discussion demonstrates that for nose-up fuselage angles of attack, the four-bottom-slot actuation configuration is suitable to reach significant drag reductions. On the other hand, for nose-down angles of attack, it is similarly identified that the four-side-slot configuration leads to the highest drag reductions. The synthesis of all fuselage drag polar measurements for all actuation configurations is plotted in Fig. 27. This figure shows that significant drag reductions can be obtained for most angles of attack: Reductions can reach 35% for negative angles of attack and 15% for positive angles of attack. Fuselage drag cannot be reduced over a limited range of angles of attack around α = 0 • . Finally, this figure emphasizes that taking the lowest values of drag envelope results in a polar of very low fuselage drag. It also demonstrates that various actuation configurations have to be used depending on the fuselage angle of attack to get this very low drag polar.

The influence of active flow control on fuselage lift is plotted in Fig. 28. This subject has not been discussed previously as lift is not a decisive objective of this investigation: Helicopter fuselages generally do not produce lift, and the aerodynamic fuselage downforce is usually limited and easily compensated by the rotor thrust. Reducing this downforce would nevertheless be an obvious benefit. The lift values corresponding to the best drag results from Fig. 27 are reported in Fig. 28. One can note that for negative angles of attack, using the four side slots, drag reductions are associated with a decrease of the fuselage downforce. Conversely, for positive angles of attack, the four-bottom-slot configurations, which are the most effective to obtain drag reductions, lead to a fuselage downforce increase.

Conclusions

Significant drag reductions on a simplified helicopter blunt fuselage have been achieved using active flow control. The comprehensive experimental study included the comparison of three types of actuation (steady blowing, unsteady blowing, and synthetic jets) for a wide range of helicopter fuselage angles of attack. The following main conclusions can be drawn from the discussed results:

1) Actuators bench tests are a critical phase of an active flow control experiment and are mandatory for a detailed overview of actuator performance and properties.

2) Large drag reductions were demonstrated for all actuators and for the whole range of angles of attack except around 0 • . Generally an average of 15-20% drag reduction is achieved.

3) Different actuations can be directly compared using the momentum coefficient C µ since it correctly represents the actuation control authority. A good consistency between the different actuation results is demonstrated.

4) For fuselage nose-down angles of attack, the reference flow is characterized by a "vortex flow" topology and the highest drag reductions are obtained using the four-side-slot configuration.

5) For fuselage nose-up angles of attack, the baseline flow is defined as an "eddy flow" and the highest drag reductions are achieved for the four-bottom-slot configuration.

6) The highest drag reductions obtained for the vortex flow are accompanied by a decrease of the fuselage downforce, whereas selected control schemes for eddy flow control are responsible for an increase of the fuselage downforce. This comprehensive experimental database has not been fully analyzed, including data such as unsteady pressure measurements on the fuselage backdoor and tail boom. Additional PIV measurements with and without active flow control have also recently been performed and will give a complementary insight into the flow control effectiveness.

NomenclatureA

  CS fuselage cross-sectional area = 0.05634 m 2 C d drag coefficient = drag/(qA CS ) C l lift coefficient = lift/(qA CS ) C p pressure coefficient C µ blowing coefficient for all jets DC pulsed jet duty cycle, DC = f *T f unsteady actuation frequency, Hz f + reduced frequency, f + = f *W /V ∞ L fuselage length = 1.0925 m l flow control slot length, m n jet number of activated jets

Fig. 1 .

 1 Fig. 1. Simplified blunt fuselage model in the wind tunnel test section.

Fig. 2 .

 2 Fig. 2. ASF2 model instrumentation: pressure taps (black) and Kulites (red).

Fig. 3 .Fig. 4 .

 34 Fig. 3. Fuselage model backdoor with the eight spaces for the removable actuators.

Fig. 5 .Fig. 6 .

 56 Fig. 5. Example of jet peak velocity measurement for the synthetic jet for several voltage inputs.

Fig. 7 .

 7 Fig. 7. Example of hot-wire measurements of peak velocity of a synthetic jet actuator over three periods for several input voltages.

Fig. 8 .

 8 Fig. 8. Example of blowing and suction semi-sine modeling based on synthetic jest laboratory measurements (symbols: measurements, solid line: semi-sine models).

Fig. 9 .

 9 Fig. 9. Baseline fuselage drag (red) and lift (blue) measurements.

Fig. 10 .Fig. 11 .

 1011 Fig. 10. Steady blowing drag measurements for eight slots and increasing jets velocity ratio VR.

Fig. 12 .Fig. 13 .

 1213 Fig. 12. Comparison of backdoor pressure distributions between steady blowing cases for eight slots and reference case for α = -5 • .

Fig. 14 .Fig. 15 .

 1415 Fig. 14. Pulsed jet actuation frequency influence for VR = 1.5, DC = 50%, and α = -5 • .

Fig. 16 .Fig. 17 .

 1617 Fig. 16. Synthetic jets drag measurements for a blowing rate VR = 2(C µ = 0.4%) and various slot configurations.

Fig. 18 .

 18 Fig. 18. Drag reduction obtained in the eddy flow region (α = 3.5 • ) for several synthetic jet actuation configurations.

Fig. 20 .

 20 Fig. 20. Comparison of backdoor pressure distributions between synthetic jet cases and reference case for α = 3.5 • (eddy flow).

Fig. 22 .

 22 Fig. 22. Synthesis of drag reduction results for vortex flow case (α =-2.5 • ) and four-side-slot configuration.

Fig. 24 .

 24 Fig. 24. Synthesis of drag reduction results for eddy flow case (α = 3.5 • ) and four-side-slot configuration.

Fig. 25 .

 25 Fig. 25. Synthesis of drag reduction results for eddy flow case (α = 3.5 • ) and four-bottom-slot configuration.

  Schaeffler et al. (Ref. 8).

Fig. 27 .

 27 Fig. 27. Synthesis of the fuselage drag reduction using steady blowing, unsteady blowing, and synthetic jets for various actuation configurations (thick black line: baseline case).

Fig. 28 .

 28 Fig. 28. Synthesis of the fuselage lift variations using steady blowing, unsteady blowing, and synthetic jets for various actuation configurations (thick black line: baseline case).

Acknowledgments

The authors would like to thank all ONERA personnel who contributed to this study, and in particular those in charge of the model and actuator design, wind tunnel setup, and running the experiment. We would also like to acknowledge the European Union for the funding of the Clean Sky project.


Published in 2019, this remarkable collection of essays not only seeks to preserve the remembrance of Peterloo but also to provide new perspectives on the event, as well as a historical reappraisal of its violence. In their perspicuous introduction to Commemorating Peterloo, Michael Demson and Regina Hewitt artfully address 'the question of what is being commemorated' (2): although the massacre is often deemed representative of a culture of violence, it should be widely remembered as 'the ultimate triumph of the people over repressive violence' (2). As Demson and Hewitt define the three notions highlighted in the subtitle of the volume ('violence, resilience, and claim-making'), they single out 'resilience' as the key term of the book and as a symbol of the reformers' 'continuing resistance to violence in all its forms' (3). Crucially, Peterloo was about identity shaping, and the gathering demonstrated 'the ability of the people to carry out normative contention' and to maintain a non-violent identity (10). Carefully articulating rather than partitioning these three notions, the twelve essays of this ambitious collection provide multi-perspectival and fresh reinterpretations of the 1819 massacre and its posterity.

The first essay by Stephen C. Behrendt appropriately extends the reflective dimension of the editors' introduction by analysing the 'moral ambivalence of the divergent responses' to Peterloo (33) and by showing how this 'collective public experience' was sometimes manipulated (35). Like many others in this volume, this essay is interspersed with various sources such as poems, satirical prints, and press articles which scripted the political identity of the people while sometimes giving a biased representation of this identity. In an ambitious essay, Ian Haywood draws attention to the 1819 massacre in an innovative waywhile most accounts make us eyewitnesses of the event, Haywood recreates its politically charged soundscape. Relying on an analogy between 'the swelling crescendo of popular protest' (58) and the sound of a volcanic eruption, Haywood's reconsideration of the aural sublime of the protestors' voice as 'bad sublime' (59) subverts Burke's anxiety about the vox populi in his Essay on the Sublime and the Beautiful (1757).

Other contributors explore different perspectives on the event, laying emphasis not only on well-known authors and political figures, but also on understudied artefacts and symbols. Murray Pittock retraces the genealogy of Henry Hunt's white hat as a non-verbal sign of sedition symbolising 'allegiance to the radical cause' (84) which complemented, but also confused the message of the more traditional red cap of Liberty. Frederick Burwick shifts attention to drama and unveils the hidden posterity of Peterloo on stage by demonstrating how the historical figure of Guy Fawkes was turned into 'a hero of the oppressed' (100), covertly spreading radical ideas despite censorship.

What makes this volume a perfect addition to the 'Edinburgh Critical Studies in Romanticism' series is its awareness of Scottish and Irish responses. Gerard Carruthers focuses on responses to Peterloo in Scotland from 1819 to 1822, underlining how 'enduringly heartfelt was the response to Peterloo and to Henry Hunt in the West of Scotland' (136). Conversely, James Kelly shows the widening gap between Ireland and England after Peterloo, as the massacre reactivated memories of 'Tory coercion' on the island (141), but also stimulated Irish eloquence. Michelle Faubert focuses on the Irish response to the massacre by contrasting Castlereagh's suicide with Peterloo as both self-sacrifice and 'ultimate betrayal' of the body politic (170), raising the issue of public sympathy. Katey Castellano's chapter brings an international dimension to the volume by considering claim-making in the United States, foregrounding William Cobbett's ambition to counter the 'animalisation of the working class' (184) in public discourse by creating a memorial for Thomas Paine in England.

The last four chapters show how Peterloo disturbs the cultural narrative of a diminishing violence in Britain by uncovering a hidden or 'dispersed' violence. John Gardner reveals how Peterloo was more important than church scandals in 'widening the rift between reformers and religion' (224). Victoria Myers analyses Jeremy Bentham's 'complex notion of violence' in his Plan of Parliamentary Reform (1817) and underlines his insight that 'non-legal (but hidden) violence was the real modus operandi of the governing class' (246). Philip Shaw argues that the massacre indirectly spurred William Wordsworth to reflect on 'the place of conflict in civil society' (252) in his post-Peterloo poetry.

Michael Scrivener's suggestive reading of the work which became the most famous denunciation of Peterloo -Percy Bysshe Shelley's The Mask of Anarchyfinally highlights the poet's call for empathy, but also for 'a repetition of Peterloo' in the future (282). This final essay aptly echoes the cover image of the volume -J. M. W. Turner's Death on a Pale Horse which is sometimes considered a representation of the fall of Anarchy (a figure modelled after Benjamin West's earlier painting with the same title) in Shelley's poem.

By bringing together these fresh perspectives on a seemingly well-known topic, the book makes an important contribution to scholarship and to the understanding of Peterloo.

Pauline Hortolland Université de Paris

Michael Demson and Regina Hewitt, eds., Commemorating Peterloo: Violence, Resilience and Claim-making during the Romantic Era. Edinburgh: Edinburgh University Press, 2019. Pp. xii + 300. £85. ISBN 9781474428569.


To cite: Joël Danet, "Stylish, snobbish, aseptic and well-mannered: Culinary art on the French TV show Dim Dam Dom." in Ana Tominc, ed., Food and Cooking on Early European Television, Routledge, 2022, pp. 72-88. Stylish, snobbish, aseptic and well-mannered: Culinary art on the French TV show Dim Dam Dom Joël Danet, Université de Strasbourg, France A dead fish is wedged in a porcelain sculpture of a Mamluk and a horse. The sound of plates being thrown to the ground, an elegant middle-aged woman wearing boxing gloves yells "Recipe for strawberry tart!", then adds in a calm voice "This one is specially dedicated to Marshal MacMahon." Animated cutlery on a black background demonstrate how to properly peel fruit. The profile of a young woman, whose hand covers the bottom of her face, shows how to "spit out a stone, the hand forming a cone." Trays filled with cream puffs and chocolate cakes are displayed in a large shop lined with columns, wood-panelled walls covered with spherical mirrors and a ceiling embellished with moulding, to which a narrator pronounces: "in a Louis XVI decor the cult of cake usually flourishes."

Such curious yet sophisticated scenes are not uncommon in 1960s French television programmes, but they particularly characterise Dim Dam Dom's approach to the culinary theme. Dim Dam Dom was a programme aimed at women that was launched in 1965 on France's 2nd television channel, 2ème chaîne de Office de radiodiffusion-télévision française (OTRF), and ran monthly until 1970. The programme's original and provocative approach, marked by snobbish content and formal style, was in sharp contrast to other culinary programmes that prevailed at the time. Although it shook up the audience with audacious performances, it did not aim at gratuitous provocation. Rather, the intention was to offer the audience a poetic, whimsical and sensual way of looking at their surroundings. Far from concentrating only on culinary topics, Dim Dam Dom was also interested in matters related to fashion, sport, and art to present the spirit of the times and new lifestyles. Each episode consisted in a sequence of short reports or segments and over the course of its productions, the programme covered a variety of topics: the French Riviera as the place to be, the boom of youth culture, the opposition of Parisian versus provincial way of life, the rise of robots in everyday life, a portrait of the bodybuilder and the yogi, to name a few. Although the breadth of topics was wide, the programme dealt with the theme of cooking regularly; 15 of the episodes include a culinary feature, with a sub-series of 9 parts dedicated to recipes. As it stems from both art and necessity, cooking seems particularly well suited to the editorial line of Dim Dam Dom, which involved taking grasp of the human body, its animal desires and needs, and covering them with a refined and distant look. The resulting productions attest to the ability to stylise life down to its most primary needs.

Here, in the context of a wider reflection on the ways in which cooking has been shown on television, it seems important to take into account this original and provocative approach. Further, analysing its biases will lead us to understand that it does not emanate from unbridled imagination, but from a critical state of mind in reaction to the choices of ordinary or more common representations.

Cooking shows were broadcast very early on French television -from 1953 -following the initiative of the Radiodiffusion-télévision française (RTF) 1 programme director Jean d'Arcy, who had been inspired by English and German examples (Roger, 2016, p. 18). Cooking shows held a constant place in French television programming. A standardized formula of the cooking shows was established early on and was long maintained, although the shows regularly changed names and slightly varied in their editorial emphases. The programmes were set in a domestic kitchen setting with easy to follow recipes, chosen because they were accessible and affordable. The shows presupposed an element of interactivity, expecting the viewer to be willing to reproduce the demonstration gestures made in front of them (or her, as it was the housewife who was targeted). Not only was the formula standardized, but there was also little change in those working behind the scenes. The director of the early French shows was Hubert Knapp (for Les recettes du chef [The Chef's Recipes] and Art et magie de la cuisine [Art and Magic of Cooking]) until 1961, followed by Gilbert Pineau (Roger, 2014, p. 69).

From 1954 to 1967, the hosts were chef Raymond Oliver and hostess Catherine Langeais. This complementary duo embodied the show's family and cultural vocation. While Raymond Oliver, who came from a prestigious restaurant background, was mobilized as a reference in the culinary arts, Catherine Langeais, nicknamed by her biographer Jean-Marc Terrasse "the fiancée of the French" for the intimacy she established with her audience (2003), embodied the ordinary television viewer able to do the dishes without having any particular qualification or professional equipment. The succession of broadcasts on the culinary theme on French television set a standard of representation from which the concurrent editions of Dim Dam Dom resolutely and systematically stand out. The latter do not take place in the kitchen and do not feature a chef; rather, they show a woman of distinguished appearance, filmed in either anonymous studio settings or rich, old parlours, literally shouting her recipes at the viewer. In contrast to the warm conviviality and domestic settings that characterize classic cooking shows, Dim Dam Dom flaunts the exuberance of its hostess and the artificial nature of its scenography; placid good humour is replaced with sharp humour and disconcerting aggressiveness. It is interesting to note that Hubert Knapp, mentioned above, joined the Dim Dam Dom directors from the very beginning of the programme. That is, he not only set up 1 RTF was the French national public broadcasting organization established in 1949. This was replaced in 1964, by the less-strictly government controlled ORTF, which itself lasted until the end of 1974. the early standard code of French culinary shows, but subsequently contributed to subverting them with Dim Dam Dom.

However, the programme's intention was not to counter prevalent performances in a spirit of nihilism or gratuitous provocation. According to the show's creator, Daisy de Galard, Dim Dam Dom responded to the expectations of public service media, and strived to adapt to its most recent developments, albeit in its own way. In a television interview she gave on Micros et caméras [Microphones and Cameras] directed by Jacques Locquin on 2 April 1966, she challenged the term "revolutionary" that the interviewer used to describe Dim Dam Dom. She stated that, like an ordinary news magazine, she wanted to "make as many people as possible aware of the problems that surround and concern them." However, she added, she wanted to do this "with the highest quality of images" (Micros et caméras, 1966). In this affirmation, she distanced herself from the trend defended by Igor Barrère or Pierre Desgraupes, who both promoted field reporting and favoured live coverage in the aim of preventing television from becoming "the cinema of the poor" through excessive artifice (Barrère, Desgraupes and Lalou, 1976, p. 15). Daisy de Galard went beyond this, adding a conceptual approach to a concern for formality. "To look smart," she added, "a problem should not be dealt with in a crude way," but by "an association of ideas." This expression refers to the psychic automatism used by the Surrealist poets of the 1920s. However, the journalist was aware that her programme would reach a large and diverse audience. She was not satisfied to have her programme praised only by "a certain category of people who say: 'it's quality, it's well-researched, it's intelligent, it's sharp'" (Micros et caméras, 1966). She wanted to reach beyond this first circle.

While she agreed that the result might "seem absurd to someone who hadn't watched it, who hadn't understood it," she wanted that reluctant viewer to just "try, turn the knob." Herein, she had a somewhat particular relation with the show's reception: it was up to the audience to adapt to her view, not the other way around. Just as André Malraux, Secrétaire d'Etat à la culture [French Secretary of State for Culture], who promoted a policy to broadcast productions that combined accessibility and elitism, Daisy de Galard was not willing to compromise on artistic and experimental ambition, or to weigh it down with explanations, even although her programme fed mass media. It must be acknowledged that at that time she benefited from a media environment that was particularly favourable to personal writing and essays. Television, just barely out of the pioneering age, was a medium that was not yet fully defined. Further, when not forced to relay official government speeches, television executives were open to formal innovation and originality of tone.

Examples of this include the variety show Les raisins verts [Green Grapes], which presented a series of unusual and cruel sketches directed by Jean-Christophe Averty (1963[START_REF] Wilde | Television archives 'La page de la femme[END_REF] or the animated television series Les shadoks [The Shadoks], an absurd tale with of bird-like creatures in somewhat recurring situations directed by cartoonist Jacques Rouxel (1968Rouxel ( -1973)). Further, the 2 nd channel launched in 1964 had a somewhat confidential character making it open to "possible experiments for programmers, different political colours" (Veyrat- Masson and Sauvage, 2012, p. 83), like Dim Dam Dom. Finally, funding through advertising had not yet begun, thus programmes were not yet required to attract the largest possible audiences, as they would be in subsequent years (Veyrat-Masson and Sauvage, 2012, p. 91). In this context, Daisy de Galard was free to pursue her editorial objective and to call on talented television directors such as: Hubert Knapp who evolved under the influence of the American school of the "subjective" documentary, Michel Polac who combined extensive literary knowledge with a subversive outlook, and Jean-Christophe Averty technical innovator inspired by Dadaism and pataphysics.2 Her recruitment policy was daring as it blurred the then increasingly marked boundaries between cinema and television. She herein managed to enlist such leading directors as Roger Vadim, who contributed to the myth of Brigitte Bardot by directing Et Dieu créa la femme (1956) […And God Created Woman], Agnès Varda, who had already made a name for herself with the feminist drama Cléo de 5 à 7 (1962) [Cléo from 5 to 7], and Guy Gilles, who embodied contemporary youth with poetry and melancholy in Au pan coupé (1967).

The editorial line that Daisy de Galard had defined for Dim Dam Dom was the same as that of the prestigious magazine Elle, for which she had previously worked. Elle and Dim Dam Dom both targeted modern, urban women interested in the trends of their time, but felt free to follow them or not, and curious about the norms of social distinction in order to adopt proper behaviour in all circumstances. It is not surprising then that the culinary segments included table manners. It was the image of oneself preparing or consuming food that was important, not the basic pleasure of preparing or consuming. In his book on the history of French cooking shows, Olivier Roger has drawn attention to the issue of self-image: "The action of a cook always constitutes a representation of the self in the sense that the decor, props or posture he adopts, in addition to the food he chooses to cook, define a situation that assigns him a determined role" (2016, p. 13). In most cooking shows, the television performer enhanced his image by competently and charismatically conforming to the audience's expectations (or to what the expectations were projected to be). It was a question of executing a recipe adapted to the domestic setting with professional brilliance. In Dim Dam Dom, the culinary act also involved self-image, but it places it in a broader field. The show was based on the constant representation of whimsical and sophisticated lifestyles, even behind the scenes of everyday life.3 It therefore takes the productions away from the kitchen and does not limit them to the preparation of the meal. Since the woman of taste must be guided through the current of worldly life, and since "culturally, eating is eating together" (Masson, 2004, p. 115), it additionally takes on the task of advising on ways to order the service and to behave during the meal.

With a study of these culinary themed sequences, we propose to ask how the treatment of cooking and eating in Dim Dam Dom contributed to the promotion of an elitist vision of society through popular media. In the first section, I will show how the choices of staging were operational in transmitting an aesthetic and dilettante vision of the subject: by stylizing gestures and spaces the labour involved in culinary activity was ignored-and the triviality of the result was highlighted. The second section will examine the foundation of the messages of savoir vivre and savoir être conveyed through content that aimed to re-codify the "imaginary table" (Boutaud, 2004), and through a transgressive staging of food preparation. Lastly, the third section will show how the programme took on an ironic view of popular practices of cooking and culinary consumption. Through implicit judgments, Dim Dam Dom invested the culinary theme in a new way and herein promoted a culture of distinction.

Sophisticated and challenging food preparation aesthetics

In the 1950s and 1960s, the culinary programmes broadcast on television in France focused on the character of the chef, dressed in white and wearing an iconic chef's hat. The set depicted a typical family kitchen and the chef adopted a "didactic attitude", adapting his actions "so that they were clearly visible to the public" (Roger, 2016, p.86). The recipes were recorded in school note-books and the prepared dishes were displayed on checker tablecloths. This staging follows rustic codes and a concern for domestic proximity. In contrast, Dim Dam Dom's culinary sequences take the opposite approach: no specialist, no kitchen decor, and no didactic effort. Above all, the resulting films display an unusual and provocative style that challenged the convention. But far from being gratuitous, this position aimed to raise awareness of contemporary trends in the relationship with food and its preparation.

Absurd staging of the recipe

It is impossible not to see the series of recipes presented by Marie-Pierre de Toulouse-Lautrec (known by her nickname Mapie) as a feat of staging. Seven of them, conceptualized and directed between 1965 and 1968 by Jean-Christophe Averty, entirely centred on Mapie's hair-raising and zany character, methodically deconstructed the typical narration of a recipe. In these short films we see a woman of distinguished appearance, in her sixties, carefully made up, wearing pearls around her neck and always wearing a strikingly elegant hat, filmed close-up, her piercing gaze penetrating the camera lens, sometimes screaming, sometimes whispering, sometimes grumbling her words, without ever yielding a smile. The set is most often either a neutral black or white background, which notably serves her staidly composed gestures, or richly decorated parlours. In any case, we never see her in a kitchen or working at a kitchen counter. The mise en scène might have risen from Mapie herself, and her noteworthy social identity. Sister of the writer Louise de Vilmorin, Marie-Pierre de Vilmorin married a cousin of the painter Henri de Toulouse-Lautrec and into a family of French nobility. Even if the television spectator might not know this, her social standing is evident in her attitude and her majestical air, as if the casting of Mapie authenticated the distinction that the programme aimed for. If in 'Le soufflé aux violettes ' (1965) [Violet soufflé] she was shown crushing violet sweets, it was with a pestle in hand and a mortar on a small table (shown close-up) and, further, in front of an old master painting (shown in the overview shot, hands and utensils no longer in the shot). Her actions were not limited to preparing the dish: sometimes she rings a bell, sometimes she blows into a kazoo, sometimes she wields a megaphone, sometimes she throws boxing punches. At times, her actions had absolutely nothing to do with preparing the recipe or even the imagery it could evoke; costumes or traditions of its country of origin, for example. Another means of interfering with the recipe involved Mapie repeating sentences at regular intervals, such as "Soufflé n'est pas joué"

["Soufflé is not playing"] (a play on words in French: soufflé is a dish, also means to bluff), or "This noise annoys me" ('Le duel de fromage blanc ', 1967) like slogans without a commercial, verses without a poem. These absurd intrusions could be seen as a touch of humour to animate the cooking lesson. But the montage itself gives them a greater importance, and they compete with the main subject. Here, the hierarchy usually established in the narrative between the main purpose (showing how to prepare a dish) and secondary elements (usually used as recreational pauses) are reversed.

The fanciful shots and artefacts (the bell, the kazoo) that break the rhythm of the culinary narrative are so frequent that the shots actually dedicated to this narrative (instructions, gestures of preparation) seem reduced to the status of cut shots, and finally, lose their meaning. Similarly, when it comes to giving the recipe for 'Recette de la tarte aux fraises ' (1967) [Recipe for strawberry tart],

Mapie repeats screaming, some of the terms of her explanation: "A crust!", or "You poke it with 550,000 stabs of a fork! ", or even "Crème patissière!" These isolated and striking phrases make us lose the thread, and deprived of their meaning, they fall into the absurd. Similarly, with Mapie's impeccably manicured hands filmed very close-up and in real time on a black background, the ordinary and necessary gesture of breaking eggs to prepare a soufflé is adorned with fleeting eroticism: everything is apparently used to shift from the film's initial register and to draw attention to suggestions unrelated to its subject. The excessive use of montage cuts wreaks havoc in the lesson, causing clashes that destabilize the gaze and undermine the content of the shots.

A programme that announces a new culinary culture

The curious staging of the food preparation scenes, described above, can be attributed largely to Jean Christophe Averty's art of directing. Elsewhere, and particularly in other Dim Dam Dom episodes on which he collaborated, he used the same neutral background to fully focus attention on the subject of the shot and to incite the eye to make "a synthesis of the image" (Jousse, 2007, p. 92).

Similarly, Mapie's recipe scenes included her original "electronic layout" process, which focused on careful image compositions and reduced, or even deny, depth of field. Finally, Mapie's provocations were undoubtedly encouraged by Averty himself. As a literary director, Averty regularly sought to infuse television content with a theatrical subversion inspired by the avant-garde Dada movement performances of the beginning of the twentieth century (Duguet, 2019, p. 100). 4 Nevertheless, Averty's style perfectly coincided with the programme's vocation as a seismograph of modern life.

The stripped-down frame corresponds to the tendency for households to seek "lightness, transparency" in the arrangements of domestic space, including and especially the kitchen. Jean-Paul Aron pointed this out, deploring "the general asepsis of the food space" that increasingly prevailed in homes in France, "which is a testimony of this [cultural] glaciation" (Aron, 1987, cited in Corbeau, 2004, p. 239). Further, we can see in the abrupt montages, as well as in the predilection for successions of short shots, a portrayal of the overall reduction in the time spent preparing food to about thirty minutes per meal in the late 1960s (Drouard, 2005, p. 145). Further, Mapie was not only trying to satisfy her own fantasy when she prepared Tahitian fish ('Poisson à la tahitienne ', 1965), recommended adding walnuts to noodles ('Recette de nouilles aux noix ', 1967) or adding corn to salad to make it "sweet as the Americans say" ('La bonne salade de Mapie ', 1965). These reflected the growing interest in the diversity of culinary trends and cultures and in risking exoticism and unexpected food combinations shown by contemporary consumers (Corbeau, 2004, p. 237). Mapie's choice of dishes, although quite simple to make, invite the spectator to discover unknown flavours.

As Alain Drouard noted, "The French were learning more and more about cooking and doing less and less of it" (2005, p. 145). Emancipated from the actual need to carry it out, Mapie's cooking lessons aimed to develop gustatory curiosity rather than to assist in meal preparation. Since Dim Dam Dom was scheduled at 9:00 p.m., Mapie's recipes were not based on meal preparation time, like other cooking shows that were broadcast between 6:00 p.m. and 7:30 p.m. The usual duration of a cooking show was 20 to 25 minutes, which is close to the time required for preparation, while a Mapie segment never lasts more than 5 minutes. The transmission of recipes served to convey knowledge and not culinary practice.

Meals as an expression of savoir vivre

4 From 1916 to 1923, the Dada movement federated artists throughout Europe who wanted to put Western culture on trial through scandalous public performances. Averty's television productions echo the Dadaist art of shocking spectators with a clinical exposure of situations and plastic compositions that diverge from good taste and morality.

In Dim Dam Dom, meal preparation is featured, as well as mealtime; cooking and eating. The collective moments when food was consumed were seen less as recreation and part of egalitarian sociability, and more as competition, in which the eating space was an arena where it was necessary to deploy one's mastery of the codes of savoir vivre to preserve one's place. However, unlike other programmes that deal with savoir vivre and "ways of the world", Dim Dam Dom did not claim any moral motivation. Knowing good table manners ensured that you were not caught lacking in elegance and education when eating with others.

Updating table manners

On several occasions, the programme treats table behaviour as an issue of socialization. One of the subjects of the programme broadcast on 28 July 1965, suggestively titled 'Savoir vivre', taught the proper way to peel fruit. This was not practical advice on how to remove the peel before eating fruit, but recommendations on how to perform this operation according to the conventions of social conduct. The production using real shots and stop motion animation techniques, signed anonymously by the Service animation de l'ORTF [ORTF animation service], is similar to those of Jean-Christophe Averty: a plain background (here it is black) on which cutlery stands out and moves, without anyone holding it, around a plate where different fruits are exhibited. As with the segments directed by Averty, the processes specific to avant-garde artists were mobilized, such as artist-photographer Man Ray's rayographs (created by placing objects directly on a sheet of photosensitized paper and exposing it to light). But unlike the Mapie series that eludes practical gestures, the 'Savoir vivre' segment scrupulously reproduces the gestures involved in peeling fruit, without rushing or interrupting them in the final editing. When demonstrating how to peel an orange, a knife sliced both ends of the fruit held in place with a fork. For the banana, a knife cut each end, split the skin and a fork removed it. With grapefruit, a spoon was used to eat the flesh.

Against a background of sirtaki music (a modern adaptation of traditional Greek music) that suggests the atmosphere of a chic restaurant, a woman's voice concluded with an indifferent tone: "It is a rule of living. At the table, nothing should be touched with your fingers. A rule that can become a stylistic exercise when it comes to peeling a fruit." There is no specification that the rule in question had also been stated in 1889 by Baronne Staffe in her treatise Usages of the World: "All fruits are peeled and eaten with the knife and dessert fork: the apple, peach or pear quarter, etc. is pricked with the fork held in the left hand, the knife in the right hand" ([1889] 2008, p. 162). The commentary in the film uses the same term "piqué" [prick] to describe what the fork does, which leads us to deduce that the author may have been familiar with Baronne's publication, or others like it.

Four months earlier, 'Des mains très bien élevées ' (1965) [Well-mannered hands], featuring the same journalist as 'Savoir vivre', Ghislaine Davezac and also using stop motion animation, detailed a series of social situations involving hands to explain the right position to adopt in certain circumstances. A Letkis tune played in the soundtrack, this Lappish dance music popularized in France in the sixties by Eddie Barclay evokes the atmosphere of worldly parties of the time. Among the various codes to be respected, one concerns table manners. We see, in a high-angle shot, a woman standing in front of a table set for a reception. One of her hands grabs a spoon to draw the soup from the soup plate in front of her, her other hand remaining flat on her thigh. To denounce this "bad habit", a male voice, bursting into the soundtrack, shouts out: "Oh no!" in a categorical tone. Immediately, a gloved hand appears from the top frame edge and raises the free hand onto the table. "Mandatory, both hands on the table!", sanctions the commentators voice, a female voice this time.

An identifying code

In its own way, Dim Dam Dom refers to the long "civilizing process" described by Norbert Elias (1969). An evolution in the methodical transformation of table manners: "Nothing in table manners", writes Elias, "'goes without saying', nothing can be considered as the result of a natural 'feeling of embarrassment'. (...) Each gesture, the way to hold and handle the knife, spoon or fork is subject to standards developed step by step" (1969, p. 231). Elias goes on to explain that this normalization is the result of a social mechanism that consisted in the diffusion of "models from the upper class" throughout society (1969, p. 232). He situated the moment when these modes were established and diffused at the end of the eighteenth century. For Daniel Roche, with regard to clothing culture, it was at the same time that the women's press took up fashion to overturn the "social logics" and promote "the female perception of the world" (1989, pp. 468-469) Dim Dam Dom emphasizes the manner that it is done; it reflected a state of mind that became second nature. "A rule can become an exercise of style" affirms the commentary in "Savoir vivre". It is precisely the "rule" that becomes the "exercise of style" which motivated the programme: such knowledge required not just discourse, but gestural mastery to express it. In this, Dim Dam Dom pursued a strategy of distinction that elevated its statements above the conformism to which it could have surrendered. When the theme of good manners was addressed, television programmes contemporary to those of Dim Dam Dom stressed their moral foundation. An episode of La page de la femme broadcast in November 1964, including a lesson in table manners given to a little boy, concluded with this comment: "table etiquette, an essential lesson for your children." A news feature, 'Ecole de charme' [Finishing school], broadcast in 1965, reported on the savoir vivre lessons that Marquis Di Favero gave to young men, in which it is explained that etiquette training could serve their professional ambitions. Another example is 'Les hôtesses de courtoisie' [Courtesy ambassadors] broadcast in 1966. 5 When questioned in a park where she was demonstrating her mastery of courteous relations, Chantal d'Astarac, the captain of an association whose mission was to spread politeness in the public space, justified her aim with these words: "Courtesy is a way to make life in society pleasant, to establish cordial relationships between people." In Dim Dam Dom, the importance of good manners was neither for education, nor for professional success, nor for civil peace, but the necessity to achieve or to maintain the rank to which we belong. Table manners were less a code of good conduct than an identifying code. The laws were given without the "essence" being explained: for the informed viewer to whom the programme was addressed, it went without saying that it was less a question of morality than of style, a notion that relates to the elevation of art of which Oscar Wilde, figure of the aesthete par excellence, defended the useless. 6Dim Dam Dom ignored the moral charge of good manners associated with food, and the show was even emancipated from it. The "decent" does not necessarily suit the codes set out. In 'Poisson à la tahitienne ' (1965) [Tahitian fish], an astonishing shot shows Mapie's two hands kneading a bowl of fish flesh and lemon, filmed very close-up. The shot was a long one, as if to insist at leisure on the spectacle of her impeccably manicured hands (able to show "refinement to the very end of the nails" like the hands shown in the programme 'Savoir vivre') as they crumble and blend the animal flesh.

The subsequent sequence was Mapie's hand pushing -alternatively the fish preparation and a baby toy -into the funnel of a grinder.

In this passage, a casual and transgressive relationship to food is displayed: it is taken up with full hands, then disembodied. Like any provocation, it is done with full knowledge of the facts, in the same way that a libertine must be a fine connoisseur of the morality he or she is violating.

"Them and us": The sanction of "franc-manger" and consumerist conformity 7 As we have stated, an ideal social type is portrayed in the mise-en-scène of Dim Dam Dom of which it's audience was assumed to be. This included men and women, especially women, of all ages but always of modern allure with cultivated casual elegance. These cultured citizens, who were aware of the challenges of behaviour in the social sphere, were no less receptive to new ways of living together. This is not shown to be a seductive lifestyle choice, but rather a model to be defended when opposed with an everyday life where conformism and lack of taste prevail. As such, it kicked out of the club "those who are not", allowing the spectators to situate themselves. Here too, this discourse is developed on the subject of cooking and eating, no longer in the mode of the lesson (this is what you must do), but that of observation (look at how they are).

Sunday picnics and cakes: Conforming habits and fads

With 'Un dimanche chez le pâtissier' [Sunday at the pastry shop], broadcast in 1965, Dim Dam Dom aimed to depict "the France of strawberry tarts", i.e. the provincial middle class that was accustomed to eating pastries every Sunday. In this segment, the commentary written by Jean Dutourd, a writer who built his reputation on his ability to take an informed and uncompromising look at contemporary bourgeois customs, uses a strong tone, enhanced by pleasant turns of phrase. The narrator depicted the ritual of going to the pastry shop "after mass before midday dinner with the family", a ritual that suited the bourgeoisie's taste for stability, and the pleasure taken in this stability: "years go by without changing its window displays, its ecstatic customers, its undecided customers." In the shots filmed by Nestor Almendros, the chain handbags, pleated skirts and Claudine collars, elements of good families' dress mix alternatively with the carefully displayed pastries. Young girls are filmed, with an indifferent look, trying to handle the cakes without clumsiness. The commentary mocked: "Look at the future besiegers of buffets, the ravenous of cocktails, the devourers of receptions. This is the most primitive form of social food gluttony, it is recommended to act early." But to see these young women clumsily seeking contentment, the time 7 Bourdieu, 1979, p. 230. for worldliness seems far away. In this respect, the film resonates with Pierre Bourdieu's observations: "the petty-bourgeois experience of the social world is first of all timidity, embarrassment of the one who feels uncomfortable in his body and in his language, who, instead of being one with them, observes them in a way from outside, with the eyes of others, monitoring and correcting himself" (Bourdieu, 1979, p. 229). Here, the camera was the "eyes of others", and the look on the young girls' faces betrays their self-conscious worry of being viewed with severity.

Another satirical film, another target category: directed in 1966 by Jacques Brissot, "Les piqueniqueurs" [The picnickers] deals with the popular enthusiasm for roadside picnics. The episode alternates views of traffic with those of a couple lying on the grass taking a nap and a family gathered around a picnic table. The commentary is composed of satisfied testimonies given by picnickers: "It's a small snack that hits the spot", "We're outdoors, we're alone." Their voices, marked by their peasant origins, roll the "r's" and are sometimes difficult to understand. Further on, the film inserted into this are images of an overturned car lying on the side of the road: the sequences of a festive meal and of a fatal accident fight for the same space. The final shot focused on the proliferation of rubbish in the grass while an operetta aria is heard: "We are happy! We're happy! We're happy!" The irony of the subject was less about the food itself than about the conditions under which it was eaten. Here too, the staging resonates with Pierre Bourdieu's observations: "The popular and bourgeois way of treating food, serving it, presenting it, offering it, which is infinitely more revealing than the very nature of the products concerned, should be subjected to a systematic comparison" (Bourdieu, 1979, p. 217).

Other people's recipes: Insufficient cooking

The central observation of Bourdieu's book La distinction (1979) to La recette du spectateur, the recipe was given as a verbal explanation from their workplace (the shop or the kiosk), without any demonstration. Dim Dam Dom's logic is maintained, that is, of not providing the means to follow the recipe but describing it in broad strokes as in a conversation. In addition, the host of 'Eux aussi ont leurs recettes' was none other than Mapie de Toulouse-Lautrec, more hair-raising than ever. Admittedly not aligning with the programme's usual ploy, Mapie adopted a posture like that of the great chef Raymond Oliver when he hosted La recette du spectateur: just as Oliver, called upon to "interpret" the spectator's recipe, to appropriate it, giving a "the demonstration of his know-how" (Roger, 2016, p. 44), Mapie did not hesitate to challenge her interviewee and criticize his choice of ingredients and his food preparation methods.

However, there was also an additional dimension: an implicit commentary, suggested in Mapie's actions, on the diversity of cuisine according to the milieu in which it is prepared. For the "duck à l'orange" it is a question of adding zest or not ('Eux aussi ont leurs recettes -un poissonnier ', 1965), and the "sautéed kidneys" of favouring champagne over white wine for basting ('Eux aussi ont leurs recettes -un opiticien ', 1965). The difference in milieu is visible in the image itself with Mapie's inimitable appearance, as she does not remove her elegant coat or bell hat, in stark contrast to that of her interviewee in his work clothes. Moreover, the very content of Mapie's remarks are intended to impose preferences that are specific to her milieu. Adding zest enhanced subtle bitter notes. Her recommendation to use champagne for cooking prompted the optician to state: "It's much more chic with champagne...". His remark, and the amused smile that accompanied it, suggest that this "ingredient" was not necessarily available in all homes. Even if she did not take notice of this insinuation, Mapie agreed, however, that "it ends up having more or less the same taste": therefore, what was at stake was the cuisine's image, which designates a distinguished way of life.

Conclusion

Dim Dam Dom continues to hold up well as a bold and demanding programme that identified and exalted the most stimulating cultural trends of the times in which it was broadcast. 8 This was largely a result of the editorial line that was maintained from one episode to the next by its creator, Daisy de 8 This may be witnessed in the retrospective honouring of the show in television shows that focused on archival clips, for example C'était [START_REF] Dim | Une visite dans les archives de la télé[END_REF], Une visite dans les archives de la télé (2004 and 2005), and Télescopie (2009).

Galard. She highlighted that quality was a priority, even if it meant shaking up the viewer's habits or expectations: "A problem must not be handled in a crude manner, it must be thought out and developed. We will obtain an image that may seem absurd to someone who has not understood it, but they are drawn in by this attention to quality" (Micros et caméras, 1966).

However, this approach was not based solely on the interest in applying art and sociology to television. It expressed a vision of the world. Dim Dam Dom played with public space as if it was a theatre of distinction. In this way, viewers were inconspicuously invited to situate themselves, whether they identified with the character who acted in this theatre with refined extravagant behaviour, or with the crowd that made up its disconcerted and entranced audience. The spectator was either someone who was "drawn in" or someone who "did not understand". It is remarkable that Dim Dam Dom invested specifically in culinary culture to promulgate this endeavour. The programme identified cuisine, food that was made and consumed, as the place where the evolution of customs is determined and where belonging is affirmed. Television, as a medium that had become popular, had amplified public space to some extent and its programmes conveying common representations to the greatest number of people. Did Dim Dam Dom's productions not aim to introduce gestures that allowed its targeted audience to project themselves and appropriate them according to their own priorities of taste and use? In this, Dim Dam Dom foreshadowed the programme Sexy Folies, also created by a woman producer Pascale Breugnot, broadcast on the same 2nd channel from 1986 to 1987. Once again episodes were framed as happenings or micro-trottoirs produced in the metro or on the street, once again a concern with evoking innovative lifestyles in real time, capable of subverting norms. It seems that Sexy Folies takes up where Dim Dam Dom left off twenty years earlier: in the city of the 1980s, and through the prism of eroticism, the show aimed to promote a new chic and feminine order within the public space, at the risk of creating a divide with those who were "drawn in", i.e., those who "did not understand", the emancipated public and the rest of the audience.

Research for this article has benefited from access to the archives of the Institut National de l 'Audiovisuel -Grand Est. This research received funding from the European Research Council (ERC) The healthy self as body capital (BodyCapital) project under the European Union's Horizon 2020 research and innovation programme (grant agreement No 694817).

Illustration 1 .

 1 Dim Dam Dom -'Recette de la tarte aux fraises'-Dir. Jean-Christophe Averty -1967 -34:45

Ilustrationl 2 .

 2 Dim Dam Dom -'Savoir vivre' -Dir. Service animation de l'ORTF / comment: Ghislaine Davezac -1965 -33:01

Illustration 3 .

 3 Dim Dam Dom -'Des mains très bien élevées' -Dir. Service animation de l'ORTF -1965 -40:43

  . However, in the episodes 'Poisson à la tahitienne' [Tahitian fish] broadcast in 1965 and 'Le punch de Mapie' [Mapie's punch] broadcast in 1968, Mapie was filmed in a richly furnished and decorated eighteenth century parlor, as a tribute to this feminist and civilizing moment in history.

Illustration 4 .

 4 Dim Dam Dom -'Poisson à la tahitienne' -Dir. Jean-Christophe Averty -1965 -36:13

  is directly relevant to the Dim Dam Dom 'Eux aussi ont leurs recettes' (1965) [They have their recipes too] segments. The title of this subseries of three films, broadcast in 1965 in three successive episodes of Dim Dam Dom, certainly referred to La recette du spectateur, [The spectator's recipe] a culinary programme launched four years earlier by RTF. In principle, La recette du spectateur reacted to previous cooking programmes, which had provided gastronomy cooking lessons applied to home economics and involving the intervention of a great chef. Driven by a concern for "closeness to the public" in Olivier Roger's words, this new programme was based on "a new form of transmission of culinary knowledge as an exchange between peers and not based on the chef's position of superiority over the public" (2016, p. 43). It was the same in Dim Dam Dom with the series 'Eux aussi ont leurs recettes' which featured a fishmonger, a candy man, and an optician delivering, in turn, their favourite recipe. Here, contrary

Pataphysics is a term and philosophical concept coined by French writer Alfred Jarry, which uses absurd irony and imaginary phenomena to portray symbolic truths.

On the notion of stage and backstage in everyday social spaces, seeGoffmann, 1959.

This association, La Courtoisie Française, continues to exist today: http://courtoisie-francaise.com/.

"All art is quite useless"(Wilde, 1890, Preface).

Illustration 5. Dim Dam Dom -'Poisson à la tahitienne' -Dir. Jean-Christophe Averty -1965 -35:31 Illustration 6. Dim Dam Dom -'Des mains très bien élevées' -Dir. Service animation de l'ORTF -1965 -41:20

Abbreviations

RTF: Radiodiffusion-télévision française [French Radio and Television Broadcasting] ORTF: Office de radiodiffusion-télévision française television [Office of French Radio and Television

Broadcasting]

INA: Institut National de l'Audiovisuel [National Audiovisual Institute]