text:
Talk:M50 motorway (Ireland)

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Curious that the Dublin orbital motorway (M50) has a number twice that of the London orbital motorway (M25)...or should I say, "doublin'" it??? Hey, you never know, someone at the Irish road ministry may have a sense of humour or perhaps they just think about things without reference to the UK!

 * Not attempting to trample on the humour, but the choice of M50 makes perfect logical sense. The M50 is a National Primary Route (therefore actually legislated for as an "N" route). All N numbers up to 33 are taken already, and those of N51 or above are National Secondary Routes.

 * N/M50 is the only memorable number available apart from perhaps N/M40. N/M34 would have been the allocation if sequential numbering was continued.

 * The only slight flaw in this explanation is that N50, although unused, may have originally been included in the secondary route number range.

 * zoney ♣ talk 22:50, 7 Jun 2005 (UTC)

The numbering method chosen is completely trivial in the greater course of things. This discussion is about as interesting as train-spotting!

 * Which 'greater course' is this? This is an article about the M50, surely the origin of the name is worth inclusion. Whether it is interesting is a different matter. Why are you here? 217.67.129.153 13:15, 14 June 2007 (UTC)

What is even more strange is that the motorway linking dublin and belfast ( irelands two main cities) is only called the M1 south of the border as the northerners have reserved the M1 title for the motorway linking Belfast and that metropolis Dungannon! maybe they just think without making reference to the outside world.

Bobtastic

Junction numbering
Contrary to recent updates on this page M50 J3 is no longer also M1 J3, it is now M1 J1 (with the Airport exit J2) unless signs have been changed very recently. See the middle of this page for the gantry southbound on the M1 for the M50 / N32 exit, it clearly bears the junction number "1". South of this is the M50 (for some reason not actually signed on this particular gantry!) I will revert the changes. --Rdd 17:27, 4 February 2007 (UTC)

J13/J14
Can someone put something about the strange limited exits and entries around junctions 13 and 14. There is a picture with a mention of the overlap. Certain journeys are impossible, such as to enter going anti-clockwise at Dundrum and then exit at Leopardstown. I guess I'm interested in the rational behind the current situation.

'''Hi. J13''' is actually a full junction, only it is in two parts. Going southbound/anti-clockwise on the M50: - you exit at Ballinteer (under the Ticknock overbridge) and down into Dundrum. To get back on at J13 you must take the parallel road south for a mile to the roundabout over the mainline at the top of Drumartin Road (Sandyford Industrial Estate). From there you can join the M50 in either direction.

J14 is a restricted junction which joins the Leopardstown Road; you can only leave the M50 if heading anti-clockwise/south; and you can only join it to head clockwise/north.

To complicate matters the on and off ramps of J14 go under the second roundabout and some ramps of J13.

So if you are heading clockwise; first you encounter, in this order; the off-ramp of J13; on-ramp J14 and a mile further on the on-ramp of J13. Going anti-clockwise; off-ramp J13, a mile further the off-ramp J14 and when you appear to have cleared all the complex of bridges you meet the off-ramp of J13.

Hence the overlapping! (Mind you, this all looks simple to the planned Red Cow and N4 junctions)!(Sarah777 06:42, 16 February 2007 (UTC))

Thanks for the information!

Now, any idea why it is that way??

I think it is to facilitate a possible future Eastern Bypass - which would join the M50 at this point - there were designs of a road of motorway standard circulated a few years back but I've heard nothing since. And maybe the fact the M50 is deeply cut into the bedrock in the vicinity of J13/14 had something to do with it. Or maybe they need the off-ramps at Ballinteer because that is where the Southern Cross section ended and they weren't sure they'd ever get to finish it! (Sarah777 12:00, 22 March 2007 (UTC))

Junction / Exit???
I notice that the article on the M50 refers to the first intersection on the M50 as Junction 1 or J1, the second as Junction 2 or J2 etc., as is common in Britian. These should really be referred to as Exit 1 Exit 2 as is the NRA standard. I notice that the use of J1, J2 has caught on amongst some drivers who have used motorways in Britain, but any official references to the motorway, and AA roadwatch etc. use Exit 1, Exit 2.

I know I am being a little pedantic, but I feel that the article should be ammended reflecting official usage. However I don't intend on editing it myself, only for it to be reverted due to "vandalism".

Regards,

LLF LaoisLeinsterFan 17:26, 19 February 2007 (UTC)

LLF. I think the 'EXIT' refers just to the off-ramp (like the 'Ausfart' on German motorways). The Junction would be the entire complex, usually one or two over-bridges and four on/off ramps. (Sarah777 22:43, 19 February 2007 (UTC))

'Junction' actually refers to when one road splits in two, eg. the M7/M9 junction, or in a railway sense Howth Junction, Limerick junction. On the M50, the road does not split in two, other roads cross the main carriageway, and slip roads connect them. The whole complex is called an intersection.

The question is however, 'Junction' seems to be the word that the general public use, so should Wikipedia reflect this, or should it reflect the official designation of 'Exit'?

Regards LaoisLeinsterFan 15:05, 20 February 2007 (UTC)

OK. So when I say 'exit' I mean 'junction' and when I say 'junction' I mean 'intersection'? That's fine by me. (Sarah777 20:21, 20 February 2007 (UTC))

It depends on your location and frame of reference - if your are on the M50 and want to leave it you use Exit 15, to join the M50 you use Junction 15. Typical AA roadwatch reports of traffic snarls are from the point of view of being on the motorway and hence say thing like "traffic is slow to Exit 2"Ashnazgul (talk) 21:13, 8 July 2010 (UTC)Ashnazgul

The NRA themselves don't seem to have a standard. They do use "Exit" a lot, but junctions are not just exits but also entry points so its incorrect. They've however used "Junction" officially before in a press release on the N11, which I can't seem to find at the moment on the website. There was also an article in the one of the Sunday newspapers last weekend (Sunday Tribune IIRC) referring to a VMS which read "J11", the writer wondering what J11 was! The developer of Carrickmines Retail Park seems intent on popularising Exit however with their ads "Exit 15 off the M50".

You could go either way, but my own vote is for Junction. Wikipedia rules are for most common name, not official name in any case, although in Ireland to use most common name would mean putting "The Lucan Road exit" etc...

--Rdd 20:31, 1 March 2007 (UTC)

Yep. And we'd have to talk about the "Mad Cow" roundabout and call Blanchardstown 'Blanch'. wiki policy is sometimes very silly....(Sarah777 01:23, 2 March 2007 (UTC))

MILES???????????????
Why are miles displayed as the prominant unit it the Fig giving the stats of the M50? it has 27 MILES ( 43 km )

I shouldn't have to remind people that Ireland uses the metric system, and though many people are familiar with miles their use is becoming less and less every day, and rarely heard anymore, kilometres are the order of the day, and have been on signs for twenty years plus and speed limits for nearly 3 years.

I would like it if the miles were removed, or put in brackets after the km if they must be kept.

(Limbo-Messiah 16:33, 23 August 2007 (UTC))

Be Bold and change it yourself. AgentPeppermint 16:36, 23 August 2007 (UTC)

I've just measured it with Google Earth and it comes out at 46 km give or take a hundred metres. That's from the start of the port Tunnel to Exit 17 with the M11 (Limbo-Messiah 16:53, 23 August 2007 (UTC))

 * Check. That's about the same distance I get scaling with my left pinkie. (Sarah777 22:25, 23 August 2007 (UTC))

Finglas rounabout
Does anyone know why the M50-N2 rounabout at Fingals has 2 gated tunnels in the centre?I have wondered about this for ages and have never been able to find an answer. Sgt baker 22:40, 29 August 2007 (UTC)

 * I have noticed this also. I reckon they were allowing for the N2 to pass under the M50 but then decided to make a more miserable junction instead - to match all the other miserable junctions on the M50. (Sarah777 23:48, 29 August 2007 (UTC))

 * Or maybe it's for Metro North? In which case the route was known 10 years ago. (Sarah777 (talk) 00:56, 9 December 2007 (UTC))

Northbound or Clockwise?
"Southbound" and "Northbound" are erroneous, especially with the opening of the Dublin Port Tunnel, as these labels were created for the initial Western Parkway section. "Northbound" refers to clockwise and "Southbound" refers to anti-clockwise relative to Dublin city centre. (taken from article).

The fact is that "Northbound/Southbound" are the terms used almost universally when referring to the M50; in common parlance, on the radio etc. Without the closure of the ring, this is pretty much accurate for all bar the tunnel.

I'm reverting the clock-references. (Sarah777 (talk) 00:53, 9 December 2007 (UTC))

Exits
I've only heard of "Exits" refered to as "Exits" and not as "J" or "Junctions". I'm from and live in Ireland. Refering to "J3" ??? They are signed as "Next Exit" and as "Exit 3" on the Motorway and HQDC or DC. And the media refer to them as "Exit"

The only Junctions I know of are the ones in the centre of Dublin and Cork. And they are street junctions for inner ring roads.

Limbo-Messiah (talk) 10:28, 18 December 2007 (UTC)

 * Not so sure. The only signs that use the term "exit" on the motorways around Dublin are signs on the motorway which advise you how to get off (or exit) the motorway. In Germany a similar situation arises with "Ausfart" used where we'd use "exit"; but the junctions are not called "Ausfarts".

 * As for common usage; roadworks signs, advance warning signs etc all use "J"; also Dublin City Council's morning traffic programme uses the term "junction" unless they specifically mean "exit". (And even then the phrase; "leave the motorway at junction 15" is far the more common usage).

 * And finally, while not wishing to pit my WP:OR against yours, I live in Dublin and the term "junction" tends to be used for the junction and "exit" only when referring to the exit; which is only part of a junction. (Sarah777 (talk) 13:11, 18 December 2007 (UTC))

 * Reading the earlier talk above; a "junction" is not synonymous with a "fork". A fork (M7/M9; exit ramps etc) is a type of junction. So is a crossroads. So is a T-junction! Again, I think we have folk confusing the word "junction" with it's various types and/or components. A motorway intersection is a junction; composed of various component junctions; forks, T-junctions, roundabout junctions etcetera. Some of these components are exits; others are entrances; off-ramps and on-ramps. (I've also noticed that "junction" is the term used most commonly by the NRA and is universally used on maps; AA, Collins; OSi and and Michelin I have to hand). - Sarah777 (talk) 13:26, 18 December 2007 (UTC)

Sara, sorry ,but I think it is an Intersection what you are refering to and not a Junction. But I've never come across anyone saying J3 or J5, doesn't sound correct. I've heard Exit 5 or Exit 7 so many times. And refering to Ausfarht in you reasearch is a bit silly as you cannot alway translate a language directly. Words can get lost in translation. The media use "the intersection of the M50 and the N3" or "Exit 6"

Dublin city council and cork city council have put up signs with J1 and J5 and so on but I've yet to hear them being used in media or by another person.

Sorry but since you will alway persist in calling it Junction and "J" ???? I won't try and change it as you will always change it back.

Limbo-Messiah (talk) 14:09, 18 December 2007 (UTC)

 * Ultimately I won't decide; if I'm wrong I'll be overruled. But in my experience "junction" (not "J", which is just shorthand - who uses "E" for exit when speaking?!) is far the most common usage except perhaps in the specific context of leaving a motorway. I was looking at the roadworks signs this evening and they have phrases such as "Use the exit at J15" or "Exit at J15". The road between "J13 and J15" will be closed between 8pm Sat to 10am Sunday to erect a Luas bridge. Etc - I can take photos if needed. And don't forget the maps - ALL of them.  Different words for different things! (Sarah777 (talk) 21:53, 18 December 2007 (UTC))

 * At the end of the day folks, you can both enter and exit a motorway at an interchange; therefore that is the correct termination. It sounds a bit mad to call them "Interchange 1", "Interchange 2" though, and so Junstion is perfectly valid and colloquailly sound.

 * The only places where these interchanges are signposted as "next exit" or "exit _" is on a motorway, not approaching one. this is because as you are already on the road, exiting it is the only alternative to continuing, thus the use of the word "exit". Ste01 (talk) 17:47, 24 July 2009 (UTC)

Fake M50 Signs
The images of the M50 signs used in the infobox are for the M50 in the UK not RoI! Compare these pics with the photograph in the article and you will see that the motorway symbol is on the wrong side! Click the images and you will find that the image names include UK in their title. Likewise the M1 & M11 signs. Peter Clarke (talk) 14:58, 29 January 2008 (UTC)
 * Yep. That's a problem; for example we get miles before kilometers. We certainly need an Irish version but I, for one, have no idea how to make these boxes. Sarah777 (talk) 00:30, 30 January 2008 (UTC)
 * Me neither. Peter Clarke (talk) 11:38, 30 January 2008 (UTC)

I can make the image in png accurately, but wouldn't now how to load it. or make the box. I'd prefer to just have km in the box too. Limbo-Messiah (talk) 15:05, 10 March 2008 (UTC)

I've made this version of the symbol using AutoCAD http://upload.wikimedia.org/wikipedia/en/1/1c/M50_motorway_IE.png Limbo-Messiah (talk) 18:21, 10 March 2008 (UTC) also m1 http://en.wikipedia.org/wiki/Image:M1_motorway_IE.pngLimbo-Messiah (talk) 18:43, 10 March 2008 (UTC) http://en.wikipedia.org/wiki/Image:M11_motorway_IE.pngLimbo-Messiah (talk) 18:45, 10 March 2008 (UTC)

 * Just noticed the m-way symbol on the wrong side (despite Peter Clarke pointing it out!). I'll have a shot at including Limbo's new png. Sarah777 (talk) 02:46, 11 March 2008 (UTC)

 * Hmmmmmm. I'm stuck! Sarah777 (talk) 02:51, 11 March 2008 (UTC)

 * I can't do it either, must have to contact someone who can design a generic motorway info box for ireland, I've changed some routes on other articles too. I'll do as many as I can.  But it takes a while as there are allot.Limbo-Messiah (talk) 11:10, 11 March 2008 (UTC)
 * Limbo, are you sure about the yellow colour on the N-route shields? Sarah777 (talk) 12:13, 11 March 2008 (UTC)

The wierd thing is that even for the UK the symbol is on the wrong side! Check out the picture on this page from a UK motorway - their start of motorway sign is identical to ours, chopsticks on right... --Rdd (talk) 14:47, 15 March 2008 (UTC)

Right, seeing as I inflicted the UK routebox on the Irish motorway pages I may as well be the one to create the Irish version. Here's Template:IRL motorway routebox for everyone to play with. I have't reinvented the wheel, just taken the UK one, made km priority over miles and added two new fields, parent is parent N-road, while N-roads is for junctions with national roads. Oh and thanks to Limbo-Messiah the symbol is on the proper side now. --Rdd (talk) 17:58, 16 March 2008 (UTC)

No problem about the correct side. And it now has a proper border to the correct spec of the Traffic Signs Manual 1996. I remade all the route shields from scratch using CAD. And they are open to public use, so anyone feel free to use them anywhere. But can it have km only in the info box. Limbo-Messiah (talk) 20:53, 16 March 2008 (UTC)

but I did the copyright thing wrong for M11 and another one. I'll fix that later.Limbo-Messiah (talk) 21:00, 16 March 2008 (UTC)

Personally I'm in favour of retaining miles as a secomdary measurement but if there is a consensus for removing it then that can be done. We don't yet know that there will be an M25 motorway, the N25 Waterford City Bypass is not being built under a Motorway Order but that doesn't preclude an order being made under the Roads Act 2007 at a future date. One hasn't been sought in the initial round of reclassifications though. --Rdd (talk) 19:32, 18 March 2008 (UTC)

 * Re the 'M'25; it is being tolled and I read somewhere that it will become (somewhat confusingly) the Irish M25. But as I can't remember where I read that I won't put it in the article....Sarah777 (talk) 22:51, 18 March 2008 (UTC)
 * Mind you, I find I keep referring to the big London Orbital as the "M50" - habits are hard to break. Sarah777 (talk) 22:53, 18 March 2008 (UTC)
 * As the person who started all this caper, I have to say - Well done everybody! Peter Clarke  12:33, 24 March 2008 (UTC)

Assessment
I see that Sarah has re-rated this article for the WikiProject Ireland from a start-class to a B-class. For an article that has no verifiable references of any kind and the two blog refs that are there fail the reference criteria. The B-class is overrated right now, especially that we have C-class as an classification. With more reference I will be happy to support a B-class assessment. Cheers ww2censor (talk) 03:41, 19 November 2008 (UTC)
 * Apologies O stern one! Forgot about the new "c"; I rarely stray from upgrading stubs to starts and follow BHG's philosophy in the matter. I read the critera and rated two other Motorway articles to "C". Dunno how I forgot about it as I was a strong advocate of introducing it. I have reverted my error. Sarah777 (talk) 06:32, 19 November 2008 (UTC)
 * That's cool Sarah, thanks. Maybe this can be improved to a B-class soon. ww2censor (talk) 14:03, 19 November 2008 (UTC)

Speed Limits
I have edited the section with reference to speed limits in the particular part of the M50 as they stand currently, to provide more detail. I have kept but rephrased the reasons for such limits being imposed, which were provided by the original author.

My reference in all cases for speed limits is personal experience as the construction limits are subject to change. Ste01 (talk) 17:40, 24 July 2009 (UTC)

Dublin Port Tunnel openeing date
The lead paragraph of the article currently states:
 * "The completed M50 motorway was formally opened on 30 June 2005, although the Dublin Port Tunnel, which had been opened on 20 December 2006, also forms part of the route."

The phrasing of this doesn't match the dates given, specifically "which had been opened" implies that the section concerned (the tunnel) opened earlier than the rest of the motorway, not later as the dates give. I don't know whether this is a stylistic problem or whether the dates given are incorrect. Thryduulf (talk) 22:03, 26 September 2009 (UTC)

 * It's a minor error. Editing it now although it wasn't me who put it there! :) Ste01 (talk) 22:34, 18 October 2009 (UTC)

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popular culture..??
Do people in Ireland sometimes refer to those within the M50 as shorthand for central Dubliners, in the same way that 'inside the M25' is used in reference to London? If so, may be worth mentioning in the article somewhere.WisDom-UK (talk) 12:11, 4 June 2020 (UTC)

title: Talk:M50 motorway (Ireland)


text:
Impatiens glandulifera

Impatiens glandulifera, Himalayan balsam, is a large annual plant native to the Himalayas. Via human introduction it is now present across much of the Northern Hemisphere and is considered an invasive species in many areas. Uprooting or cutting the plants is an effective means of control.

In Europe, Himalayan balsam has been included since 2017 in the list of Invasive Alien Species of Union concern (the Union list). This implies that the species cannot be imported, cultivated, transported, commercialized, planted, or intentionally released into the environment in the whole of the European Union.

Etymology
The common names Himalayan balsam and kiss-me-on-the-mountain refer to the plant's native Himalayan mountains. Ornamental jewelweed refers to its cultivation as an ornamental plant.

The specific epithet glandulifera is a compound word from glándula meaning 'small gland', and ferre meaning 'to bear'.

Description
It typically grows to 1 to 2 m high, with a soft green or red-tinged stem, and lanceolate leaves 5 to 23 cm long. The crushed foliage has a strong musty smell. Below the leaf stems the plant has glands that produce a sticky, sweet-smelling, and edible nectar. The flowers are pink, with a hooded shape, 3 to 4 cm ($1 1/4$ to $1 1/2$ in) tall and 2 cm ($3/4$ in) broad; the flower shape has been compared to a policeman's helmet.

After flowering between June and October, the plant forms seed pods 2 to 3 cm ($3/4$ to $1 1/4$ in) long and 8 mm broad ($1/4$ in), which explode when disturbed, scattering the seeds up to 7 m.

The green seed pods, seeds, young leaves and shoots are all edible. The flowers can be turned into a jam or parfait.

The plant was rated in first place for per day nectar production per flower in a UK plants survey conducted by the AgriLand project which is supported by the UK Insect Pollinators Initiative. However, when number of flowers per floral unit, flower abundance, and phenology were taken into account, it dropped out of the top ten for most nectar per unit cover per year, as did all plants that placed in the top ten for per-day nectar production per flower, with the exception of common comfrey (Symphytum officinale).

Distribution and habitat
Himalayan balsam is native to the Himalayas, specifically to the areas between Kashmir and Uttarakhand. In its native range it is usually found at altitudes between 2000 and 2500 m above sea level, although it has been reported at up to 4000 m above sea level.

In Europe the plant was first introduced into the United Kingdom by John Forbes Royle, professor of medicine at King's College, London who became Superintendent of the Botanic Gardens, Saharanpur, India. It has now become naturalized and widespread across riverbanks. At present it can be found almost everywhere across the continent.

In North America it has been found in the Canadian provinces of British Columbia, Manitoba, Ontario, Quebec, Nova Scotia, New Brunswick, Prince Edward Island and Newfoundland. In the United States it is found on both the east and west coast, seemingly restricted to northern latitudes.

In New Zealand it is sometimes found growing wild along riverbanks and wetlands.

Invasive species
Himalayan balsam is sometimes cultivated for its flowers. It is now widely established in other parts of the world (such as the British Isles and North America), in some cases becoming a weed. Its aggressive seed dispersal, coupled with high nectar production which attracts pollinators, often allows it to out-compete native plants. Himalayan balsam also promotes river bank erosion due to the plant dying back over winter, leaving the bank unprotected from flooding. Invasive Himalayan balsam can also adversely affect indigenous species by attracting pollinators (e.g. insects) at the expense of indigenous species. It is considered a "prohibited noxious weed" under the Alberta Weed Control Act 2010.

In the UK, the plant was first introduced in 1839, at the same time as giant hogweed and Japanese knotweed. These plants were all promoted at the time as having the virtues of "herculean proportions" and "splendid invasiveness" which meant that ordinary people could buy them for the cost of a packet of seeds to rival the expensive orchids grown in the greenhouses of the rich. Within ten years, however, Himalayan balsam had escaped from the confines of cultivation and begun to spread along the river systems of England.

It has now spread across most of the UK, and some local wildlife trusts organise "balsam bashing" events to help control the plant. However, a study by Hejda and Pyšek (2006) concluded that, in some circumstances, such efforts may cause more harm than good. Destroying riparian stands of Himalayan balsam can open up the habitat for more aggressive invasive plants such as Japanese knotweed and aid in seed dispersal by dropped seeds sticking to shoes. Riparian habitat is suboptimal for I. glandulifera, and spring or autumn flooding destroys seeds and plants. The research suggests that the best way to control the spread of riparian Himalayan balsam is to decrease eutrophication, thereby permitting the better-adapted local vegetation, that gets outgrown by the balsam on watercourses with high nutrient load, to rebound naturally. The researchers caution that their conclusions probably do not hold true for stands of the plant at forest edges and meadow habitats, where manual destruction is still the best approach.

The Bionic Control of Invasive Weeds project, in Wiesbaden, Germany, is trying to establish a self-sufficient means of conserving their local biodiversity by developing several food products made from the Himalayan balsam flowers. If all goes well, the project will have it financing its own eradication.

In August 2014, CABI released a rust fungus in Berkshire, Cornwall and Middlesex in the United Kingdom as part of field trials into the biological control of Himalayan balsam.

Some research also suggests that I. glandulifera may exhibit allelopathy, which means that it excretes toxins that negatively affect neighboring plants, thus increasing its competitive advantage.

The Royal Horticultural Society and the Centre for Ecology and Hydrology recommend that pulling and cutting is the main method of non-chemical control, and usually the most appropriate. Natural Resources Wales has used manual methods, such as pulling plants and using strimmers, to largely eradicate Himalayan balsam from reaches of the River Ystwyth.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Impatiens glandulifera


text:
Allison J35

The General Electric/Allison J35 was the United States Air Force's first axial-flow (straight-through airflow) compressor jet engine. Originally developed by General Electric (GE company designation TG-180) in parallel with the Whittle-based centrifugal-flow J33, the J35 was a fairly simple turbojet, consisting of an eleven-stage axial-flow compressor and a single-stage turbine. With the afterburner, which most models carried, it produced a thrust of 7400 lbf.

Like the J33, the design of the J35 originated at General Electric, but major production was by the Allison Engine Company.

Design and development
While developing the T31 axial turboprop in 1943 General Electric realized that they had the resources to design an axial flow turbojet at the same time as their centrifugal-flow J33 engine. They recognized the axial would have more potential for the future and went ahead with the TG-180 engine. GE axial compressor designs were developed from the NACA 8-stage compressor. The engine had its starter and accessories (fuel control, fuel pump, oil pumps, hydraulic pump, RPM generator) mounted in the center of the compressor inlet. This accessory layout, as used on centrifugal engines, restricted the area available for compressor inlet air. It was carried over to the J47 but revised (relocated to an external gearbox) on the J73 when a 50% increase in airflow was required. It also had an inlet debris guard which was common on early jet engines.

GE developed a variable afterburner for the engine, although electronic control linked with engine controls had to wait until the J47. Marrett describes one of the potential consequences of manual control of the engine and afterburner on a turbine engine: if the afterburner lit but the pilot failed to ensure the nozzle opened, the RPM governor could overfuel the engine until the turbine failed.

Operational history
The General Electric J35 first flew in the Republic XP-84 Thunderjet in 1946. Late in 1947, complete responsibility for the development and production of the engine was transferred to the Allison Division of the General Motors Corporation and some J35s were also built by GM's Chevrolet division. More than 14,000 J35s had been built by the time production ended in 1955.

The J35 was used to power the Bell X-5 variable-sweep research aircraft and various prototypes such as the Douglas XB-43 Jetmaster, North American XB-45 Tornado, Convair XB-46, Boeing XB-47 Stratojet, Martin XB-48, and Northrop YB-49. It is probably best known, however, as the engine used in two of the leading fighters of the United States Air Force (USAF) in the 1950s: the Republic F-84 Thunderjet and the Northrop F-89 Scorpion.

A largely redesigned development, the J35-A-23, was later produced as the Allison J71, developing 10900 lbf thrust.

Variants
Data from: Aircraft Engines of the World 1953, Aircraft Engines of the World 1950

 * J35-GE-2: 3,820 lbf thrust, prototypes built by General Electric.
 * J35-GE-7: 3,745 lbf thrust, built by General Electric, powered the 2 Republic XP-84 Thunderjet prototypes
 * J35-GE-15: 4000 lbf thrust, built by General Electric, powered the sole Republic XP-84A Thunderjet
 * J35-A-3: 4000 lbf thrust
 * J35-C-3: 3,820 lbf thrust, production by Chevrolet.
 * J35-C-3: 4000 lbf thrust, production by Chevrolet.
 * J35-A-4: Similar to -29, 4000 lbf thrust
 * J35-A-5: 4000 lbf thrust
 * J35-A-9: 4000 lbf thrust
 * J35-A-11: Similar to -29, 6000 lbf thrust
 * J35-A-13: 5200 lbf thrust
 * J35-A-13C:
 * J35-A-15: Similar to -29, 4000 lbf thrust, powered the 15 Republic YP-84 Thunderjets
 * J35-A-15C: 4000 lbf thrust
 * J35-A-17: Similar to -29, 4900 lbf thrust
 * J35-A-17A: Similar to -29, 5000 lbf thrust
 * J35-A-17D: 5000 lbf thrust
 * J35-A-19: Similar to -17, 5000 lbf thrust
 * J35-A-21: Similar to -35, 5600 lbf thrust, 7400 lbf with afterburner
 * J35-A-21A: Similar to -35, 5600 lbf thrust, 7400 lbf with afterburner
 * J35-A-23: Similar to -29, 10900 lbf thrust, original designation for the Allison J71
 * J35-A-25: Similar to -29, 5000 lbf thrust
 * J35-A-29: 5560 lbf thrust
 * J35-A-33: Similar to -35, 5600 lbf thrust, 7400 lbf with afterburner, without anti-icing
 * J35-A-33A: Similar to -35, 5600 lbf thrust, 7400 lbf with afterburner, without anti-icing
 * J35-A-35: 5440 lbf thrust, 7200 lbf with afterburner
 * J35-A-41: Similar to -35, 5600 lbf thrust, 7400 lbf with afterburner, with anti-icing
 * Model 450:company designation for J35 series engines.
 * General Electric 7E-TG-180-XR-17A : ca 1740 hp gas power, gas generator for the Hughes XH-17.

Applications

 * Bell X-5
 * Boeing XB-47 Stratojet
 * Convair XB-46
 * Douglas D-558-1 Skystreak
 * Douglas XB-43 Jetmaster
 * Fiat G.80 (proposal only)
 * Hughes XH-17 (experimental helicopter)
 * Martin XB-48
 * North American FJ-1 Fury
 * North American XB-45 Tornado
 * North American XP-86 Sabre
 * Northrop F-89 Scorpion
 * Northrop YB-49
 * Republic F-84 Thunderjet
 * Vought F7U-3 Cutlass (interim test usage)

Engines on display

 * Allison J35 is on public display at Texas Air Museum - Stinson Chapter, San Antonio, Texas
 * Allison J35 is on public display at San Jose State University, San Jose, California
 * Allison J35 is on public display at Flyhistorisk Museum, Sola, Norway

title: Allison J35


text: Talk:Impatiens

title: Talk:Impatiens


text:
Smoothed-particle hydrodynamics

Smoothed-particle hydrodynamics (SPH) is a computational method used for simulating the mechanics of continuum media, such as solid mechanics and fluid flows. It was developed by Gingold and Monaghan and Lucy in 1977, initially for astrophysical problems. It has been used in many fields of research, including astrophysics, ballistics, volcanology, and oceanography. It is a meshfree Lagrangian method (where the co-ordinates move with the fluid), and the resolution of the method can easily be adjusted with respect to variables such as density.

Advantages

 * By construction, SPH is a meshfree method, which makes it ideally suited to simulate problems dominated by complex boundary dynamics, like free surface flows, or large boundary displacement.
 * The lack of a mesh significantly simplifies the model implementation and its parallelization, even for many-core architectures.

 * SPH can be easily extended to a wide variety of fields, and hybridized with some other models, as discussed in Modelling Physics.
 * As discussed in section on weakly compressible SPH, the method has great conservation features.
 * The computational cost of SPH simulations per number of particles is significantly less than the cost of grid-based simulations per number of cells when the metric of interest is related to fluid density (e.g., the probability density function of density fluctuations). This is the case because in SPH the resolution is put where the matter is.

Limitations

 * Setting boundary conditions in SPH such as inlets and outlets and walls is more difficult than with grid-based methods. In fact, it has been stated that "the treatment of boundary conditions is certainly one of the most difficult technical points of the SPH method".  This challenge is partly because in SPH the particles near the boundary change with time.  Nonetheless, wall boundary conditions for SPH are available.
 * The computational cost of SPH simulations per number of particles is significantly larger than the cost of grid-based simulations per number of cells when the metric of interest is not (directly) related to density (e.g., the kinetic-energy spectrum). Therefore, overlooking issues of parallel speedup, the simulation of constant-density flows (e.g., external aerodynamics) is more efficient with grid-based methods than with SPH.

Fluid dynamics

Smoothed-particle hydrodynamics is being increasingly used to model fluid motion as well. This is due to several benefits over traditional grid-based techniques. First, SPH guarantees conservation of mass without extra computation since the particles themselves represent mass. Second, SPH computes pressure from weighted contributions of neighboring particles rather than by solving linear systems of equations. Finally, unlike grid-based techniques, which must track fluid boundaries, SPH creates a free surface for two-phase interacting fluids directly since the particles represent the denser fluid (usually water) and empty space represents the lighter fluid (usually air). For these reasons, it is possible to simulate fluid motion using SPH in real time. However, both grid-based and SPH techniques still require the generation of renderable free surface geometry using a polygonization technique such as metaballs and marching cubes, point splatting, or 'carpet' visualization. For gas dynamics it is more appropriate to use the kernel function itself to produce a rendering of gas column density (e.g., as done in the SPLASH visualisation package).

One drawback over grid-based techniques is the need for large numbers of particles to produce simulations of equivalent resolution. In the typical implementation of both uniform grids and SPH particle techniques, many voxels or particles will be used to fill water volumes that are never rendered. However, accuracy can be significantly higher with sophisticated grid-based techniques, especially those coupled with particle methods (such as particle level sets), since it is easier to enforce the incompressibility condition in these systems. SPH for fluid simulation is being used increasingly in real-time animation and games where accuracy is not as critical as interactivity.

Recent work in SPH for fluid simulation has increased performance, accuracy, and areas of application:

 * B. Solenthaler, 2009, develops Predictive-Corrective SPH (PCISPH) to allow for better incompressibility constraints
 * M. Ihmsen et al., 2010, introduce boundary handling and adaptive time-stepping for PCISPH for accurate rigid body interactions
 * K. Bodin et al., 2011, replace the standard equation of state pressure with a density constraint and apply a variational time integrator
 * R. Hoetzlein, 2012, develops efficient GPU-based SPH for large scenes in Fluids v.3
 * N. Akinci et al., 2012, introduce a versatile boundary handling and two-way SPH-rigid coupling technique that is completely based on hydrodynamic forces; the approach is applicable to different types of SPH solvers
 * M. Macklin et al., 2013 simulates incompressible flows inside the Position Based Dynamics framework, for bigger timesteps
 * N. Akinci et al., 2013, introduce a versatile surface tension and two-way fluid-solid adhesion technique that allows simulating a variety of interesting physical effects that are observed in reality
 * J. Kyle and E. Terrell, 2013, apply SPH to Full-Film Lubrication
 * A. Mahdavi and N. Talebbeydokhti, 2015, propose a hybrid algorithm for implementation of solid boundary condition and simulate flow over a sharp crested weir
 * S. Tavakkol et al., 2016, develop curvSPH, which makes the horizontal and vertical size of particles independent and generates uniform mass distribution along curved boundaries
 * W. Kostorz and A. Esmail-Yakas, 2020, propose a general, efficient and simple method for evaluating normalization factors near piecewise-planar boundaries
 * Colagrossi et al., 2019, study flow around a cylinder close to a free-surface and compare with other techniques

Astrophysics
Smoothed-particle hydrodynamics's adaptive resolution, numerical conservation of physically conserved quantities, and ability to simulate phenomena covering many orders of magnitude make it ideal for computations in theoretical astrophysics.

Simulations of galaxy formation, star formation, stellar collisions, supernovae and meteor impacts are some of the wide variety of astrophysical and cosmological uses of this method.

SPH is used to model hydrodynamic flows, including possible effects of gravity. Incorporating other astrophysical processes which may be important, such as radiative transfer and magnetic fields is an active area of research in the astronomical community, and has had some limited success.

Solid mechanics
Libersky and Petschek extended SPH to Solid Mechanics. The main advantage of SPH in this application is the possibility of dealing with larger local distortion than grid-based methods. This feature has been exploited in many applications in Solid Mechanics: metal forming, impact, crack growth, fracture, fragmentation, etc.

Another important advantage of meshfree methods in general, and of SPH in particular, is that mesh dependence problems are naturally avoided given the meshfree nature of the method. In particular, mesh alignment is related to problems involving cracks and it is avoided in SPH due to the isotropic support of the kernel functions. However, classical SPH formulations suffer from tensile instabilities and lack of consistency. Over the past years, different corrections have been introduced to improve the accuracy of the SPH solution, leading to the RKPM by Liu et al. Randles and Libersky and Johnson and Beissel tried to solve the consistency problem in their study of impact phenomena.

Dyka et al. and Randles and Libersky introduced the stress-point integration into SPH and Ted Belytschko et al. showed that the stress-point technique removes the instability due to spurious singular modes, while tensile instabilities can be avoided by using a Lagrangian kernel. Many other recent studies can be found in the literature devoted to improve the convergence of the SPH method.

Recent improvements in understanding the convergence and stability of SPH have allowed for more widespread applications in Solid Mechanics. Other examples of applications and developments of the method include:

 * Metal forming simulations.
 * SPH-based method SPAM (Smoothed Particle Applied Mechanics) for impact fracture in solids by William G. Hoover.
 * Modified SPH (SPH/MLSPH) for fracture and fragmentation.
 * Taylor-SPH (TSPH) for shock wave propagation in solids.
 * Generalized coordinate SPH (GSPH) allocates particles inhomogeneously in the Cartesian coordinate system and arranges them via mapping in a generalized coordinate system in which the particles are aligned at a uniform spacing.

Interpolations
The Smoothed-Particle Hydrodynamics (SPH) method works by dividing the fluid into a set of discrete moving elements $$ i,j $$, referred to as particles. Their Lagrangian nature allows setting their position $$ \mathbf{r}_i $$ by integration of their velocity $$ \mathbf{v}_i $$ as:

\frac{\mathrm{d}\boldsymbol{r}_i}{\mathrm{d}t}=\boldsymbol{v}_i. $$

These particles interact through a kernel function with characteristic radius known as the "smoothing length", typically represented in equations by $$ h $$. This means that the physical quantity of any particle can be obtained by summing the relevant properties of all the particles that lie within the range of the kernel, the latter being used as a weighting function $$ W $$. This can be understood in two steps. First an arbitrary field $$ A $$ is written as a convolution with $$ W $$:

A(\boldsymbol{r}) = \int A\left(\boldsymbol{r^{\prime}}\right) W(| \boldsymbol{r}-\boldsymbol{r^{\prime}} |,h) \, \mathrm{d}V \! \left(\boldsymbol{r'}\right). $$

The error in making the above approximation is order $$ h^2 $$. Secondly, the integral is approximated using a Riemann summation over the particles:

A(\boldsymbol{r}) = \sum_j V_j A_j W(| \boldsymbol{r}-\boldsymbol{r}_{j} |,h), $$

where the summation over $$ j $$ includes all particles in the simulation. $$ V_j $$ is the volume of particle $$ j $$, $$ A_j $$ is the value of the quantity $$ A $$ for particle $$ j $$ and $$\boldsymbol{r}$$ denotes position. For example, the density $$ \rho_i $$ of particle $$ i $$ can be expressed as:

\rho_i = \rho(\boldsymbol{r}_i) = \sum_j m_j W_{ij}, $$

where $$ m_j = \rho_j V_j $$ denotes the particle mass and $$ \rho_j $$ the particle density, while $$ W_{ij}=W_{ji} $$ is a short notation for $$ W(| \boldsymbol{r}_i-\boldsymbol{r}_j |,h) $$. The error done in approximating the integral by a discrete sum depends on $$ h $$, on the particle size (i.e. $$ V_j^{1/d} $$, $$ d $$ being the space dimension), and on the particle arrangement in space. The latter effect is still poorly known.

Kernel functions commonly used include the Gaussian function, the quintic spline and the Wendland $$ C^2 $$ kernel. The latter two kernels are compactly supported (unlike the Gaussian, where there is a small contribution at any finite distance away), with support proportional to $$ h $$. This has the advantage of saving computational effort by not including the relatively minor contributions from distant particles.

Although the size of the smoothing length can be fixed in both space and time, this does not take advantage of the full power of SPH. By assigning each particle its own smoothing length and allowing it to vary with time, the resolution of a simulation can be made to automatically adapt itself depending on local conditions. For example, in a very dense region where many particles are close together, the smoothing length can be made relatively short, yielding high spatial resolution. Conversely, in low-density regions where individual particles are far apart and the resolution is low, the smoothing length can be increased, optimising the computation for the regions of interest.

Discretization of governing equations
For particles of constant mass, differentiating the interpolated density $$ \rho_i $$ with respect to time yields

\frac{d\rho_i}{dt} = \sum_j m_j \left(\boldsymbol{v}_i - \boldsymbol{v}_j\right) \cdot \nabla W_{ij}, $$

where $$ \nabla W_{ij}=-\nabla W_{ji} $$ is the gradient of $$ W_{ij} $$ with respect to $$ \boldsymbol{r}_i $$. Comparing this equation with the continuity equation in the Lagrangian description (using material derivatives),

\frac{d\rho}{dt} = -\rho \nabla \cdot \boldsymbol{v} , $$

it is apparent that its right-hand side is an approximation of $$ -\rho \nabla \cdot \mathbf{v} $$; hence one defines a discrete divergence operator as follows:

\operatorname{D}_i\left\{ \boldsymbol{v}_j \right\} = -\frac{1}{\rho_i} \sum_j m_j \left(\boldsymbol{v}_i - \boldsymbol{v}_j\right) \cdot \nabla W_{ij}. $$

This operator gives an SPH approximation of $$ \nabla \cdot \mathbf{v} $$ at the particle $$ i $$ for a given set of particles with given masses $$ m_j $$, positions $$ \left\{ \mathbf{r}_j \right\} $$ and velocities $$ \left\{ \mathbf{v}_j \right\} $$.

The other important equation for a compressible inviscid fluid is the Euler equation for momentum balance:

\frac{d\boldsymbol{v}}{dt} = -\frac{1}{\rho}\nabla p + \boldsymbol{g} $$

Similarly to continuity, the task is to define a discrete gradient operator in order to write

\frac{d\boldsymbol{v}_i}{dt} = -\frac{1}{\rho} \operatorname{\mathbf{G}}_i \left\{ p_j \right\} + \boldsymbol{g} $$

One choice is

\operatorname{\mathbf{G}}_i\left\{ p_j \right\} = \rho_i \sum_j m_j \left(\frac{p_i}{\rho_i^2} + \frac{p_j}{\rho_j^2}\right) \nabla W_{ij}, $$

which has the property of being skew-adjoint with the divergence operator above, in the sense that

\sum_i V_i \boldsymbol{v}_i \cdot \operatorname{\mathbf{G}}_i \left\{ p_j \right\} = - \sum_i V_i p_i \operatorname{D}_i\left\{ \boldsymbol{v}_j \right\} , $$

this being a discrete version of the continuum identity

\int \boldsymbol{v} \cdot \operatorname{grad} p = - \int p \operatorname{div} \cdot \boldsymbol{v}. $$

This property leads to nice conservation properties.

Notice also that this choice leads to a symmetric divergence operator and antisymmetric gradient. Although there are several ways of discretizing the pressure gradient in the Euler equations, the above antisymmetric form is the most acknowledged one. It supports strict conservation of linear and angular momentum. This means that a force that is exerted on particle $$i$$ by particle $$j$$ equals the one that is exerted on particle $$j$$ by particle $$i$$ including the sign change of the effective direction, thanks to the antisymmetry property $$ \nabla W_{ij}=-\nabla W_{ji} $$.

Nevertheless, other operators have been proposed, which may perform better numerically or physically. For instance, one drawback of these operators is that while the divergence $$ \operatorname{D} $$ is zero-order consistent (i.e. yields zero when applied to a constant vector field), it can be seen that the gradient $$ \operatorname{\mathbf{G}} $$ is not. Several techniques have been proposed to circumvent this issue, leading to renormalized operators (see e.g. ).

Variational principle
The above SPH governing equations can be derived from a least action principle, starting from the Lagrangian of a particle system:

\mathcal{L} = \sum_j m_j \left( \tfrac{1}{2}\boldsymbol{v}_j^2 -e_j +\boldsymbol{g}\cdot\boldsymbol{r}_j \right) $$,

where $$ e_j $$ is the particle specific internal energy. The Euler–Lagrange equation of variational mechanics reads, for each particle:

\frac{\mathrm{d}}{\mathrm{d}t} \frac{\partial\mathcal{L}}{\partial\boldsymbol{v}_i} = \frac{\partial\mathcal{L}}{\partial\boldsymbol{r}_i}. $$

When applied to the above Lagrangian, it gives the following momentum equation:

m_i \frac{\mathrm{d}\boldsymbol{v}_i}{\mathrm{d}t} = -\sum_j m_j \frac{\partial e_j}{\partial\boldsymbol{r}_i} + m_i \boldsymbol{g} = -\sum_j m_j \frac{\partial e_j}{\partial\rho_j}\frac{\partial\rho_j}{\partial\boldsymbol{r}_i} + m_i \boldsymbol{g} $$

where the chain rule has been used, since $$ e_j $$ depends on $$ \rho_j $$, and the latter, on the position of the particles. Using the thermodynamic property $$ \mathrm{d}e = \left(p/\rho^2\right)\mathrm{d}\rho $$ we may write

m_i \frac{\mathrm{d}\boldsymbol{v}_i}{\mathrm{d}t} = -\sum_j m_j \frac{p_j}{\rho_j^2}\frac{\partial\rho_j}{\partial\boldsymbol{r}_i} + m_i \boldsymbol{g} , $$

Plugging the SPH density interpolation and differentiating explicitly $$ \tfrac{\partial\rho_j}{\partial\boldsymbol{r}_i} $$ leads to

\frac{\mathrm{d}\boldsymbol{v}_i}{\mathrm{d}t} = - \sum_j m_j \left(\frac{p_i}{\rho_i^2} + \frac{p_j}{\rho_j^2}\right) \nabla W_{ij} + \boldsymbol{g} , $$

which is the SPH momentum equation already mentioned, where we recognize the $$ \operatorname{\mathbf{G}} $$ operator. This explains why linear momentum is conserved, and allows conservation of angular momentum and energy to be conserved as well.

Time integration
From the work done in the 80's and 90's on numerical integration of point-like particles in large accelerators, appropriate time integrators have been developed with accurate conservation properties on the long term; they are called symplectic integrators. The most popular in the SPH literature is the leapfrog scheme, which reads for each particle $$ i $$:

 * $$\begin{align}

\boldsymbol{v}_i^{n+1/2} &= \boldsymbol{v}_i^n + \boldsymbol{a}_i^n \frac{\Delta t}{2}, \\ \boldsymbol{r}_i^{n+1} &= \boldsymbol{r}_i^n + \boldsymbol{v}_i^{i+1/2}\Delta t,\\ \boldsymbol{v}_i^{n+1} &= \boldsymbol{v}_i^{n+1/2} + \boldsymbol{a}_i^{i+1} \frac{\Delta t}{2}, \end{align}$$

where $$ \Delta t $$ is the time step, superscripts stand for time iterations while $$ \boldsymbol{a}_i $$ is the particle acceleration, given by the right-hand side of the momentum equation.

Other symplectic integrators exist (see the reference textbook ). It is recommended to use a symplectic (even low-order) scheme instead of a high order non-symplectic scheme, to avoid error accumulation after many iterations.

Integration of density has not been studied extensively (see below for more details).

Symplectic schemes are conservative but explicit, thus their numerical stability requires stability conditions, analogous to the Courant-Friedrichs-Lewy condition (see below).

Boundary techniques

In case the SPH convolution shall be practiced close to a boundary, i.e. closer than $s · h$, then the integral support is truncated. Indeed, when the convolution is affected by a boundary, the convolution shall be split in 2 integrals,

A(\boldsymbol{r}) = \int_{\Omega(\boldsymbol{r})} A\left(\boldsymbol{r^{\prime}}\right) W(| \boldsymbol{r}-\boldsymbol{r^{\prime}} |,h) d\boldsymbol{r^{\prime}} + \int_{B(\boldsymbol{r}) - \Omega(\boldsymbol{r})} A\left(\boldsymbol{r^{\prime}}\right) W(| \boldsymbol{r}-\boldsymbol{r^{\prime}} |,h) d\boldsymbol{r^{\prime}}, $$

where $B(r)$ is the compact support ball centered at $r$, with radius $s · h$, and $Ω(r)$ denotes the part of the compact support inside the computational domain, $Ω ∩ B(r)$. Hence, imposing boundary conditions in SPH is completely based on approximating the second integral on the right hand side. The same can be of course applied to the differential operators computation,

\nabla A(\boldsymbol{r}) = \int_{\Omega(\boldsymbol{r})} A\left(\boldsymbol{r^{\prime}}\right) \nabla W(\boldsymbol{r}-\boldsymbol{r^{\prime}},h) d\boldsymbol{r^{\prime}} + \int_{B(\boldsymbol{r}) - \Omega(\boldsymbol{r})} A\left(\boldsymbol{r^{\prime}}\right) \nabla W(\boldsymbol{r}-\boldsymbol{r^{\prime}},h) d\boldsymbol{r^{\prime}}. $$

Several techniques has been introduced in the past to model boundaries in SPH.

Integral neglect

The most straightforward boundary model is neglecting the integral,

\int_{B(\boldsymbol{r}) - \Omega(\boldsymbol{r})} A\left(\boldsymbol{r^{\prime}}\right) \nabla W(\boldsymbol{r}-\boldsymbol{r^{\prime}},h) d\boldsymbol{r^{\prime}} \simeq \boldsymbol{0}, $$

such that just the bulk interactions are taken into account,

\nabla A_i = \sum_{j \in \Omega_i} V_j A_j \nabla W_{ij}. $$

This is a popular approach when free-surface is considered in monophase simulations.

The main benefit of this boundary condition is its obvious simplicity. However, several consistency issues shall be considered when this boundary technique is applied. That's in fact a heavy limitation on its potential applications.

Fluid Extension

Probably the most popular methodology, or at least the most traditional one, to impose boundary conditions in SPH, is Fluid Extension technique. Such technique is based on populating the compact support across the boundary with so-called ghost particles, conveniently imposing their field values.

Along this line, the integral neglect methodology can be considered as a particular case of fluid extensions, where the field, $A$, vanish outside the computational domain.

The main benefit of this methodology is the simplicity, provided that the boundary contribution is computed as part of the bulk interactions. Also, this methodology has been deeply analyzed in the literature.

On the other hand, deploying ghost particles in the truncated domain is not a trivial task, such that modelling complex boundary shapes becomes cumbersome. The 2 most popular approaches to populate the empty domain with ghost particles are Mirrored-Particles and Fixed-Particles.

Boundary Integral

The newest Boundary technique is the Boundary Integral methodology. In this methodology, the empty volume integral is replaced by a surface integral, and a renormalization:

\nabla A_i = \frac{1}{\gamma_i} \left( \sum_{j \in \Omega_i} V_j A_j \nabla W_{ij} + \sum_{j \in \partial \Omega_i} S_j A_j \boldsymbol{n}_j W_{ij} \right), $$

\gamma_i = \sum_{j \in \Omega_i} V_j W_{ij}, $$

with $n_{j}$ the normal of the generic j-th boundary element. The surface term can be also solved considering a semi-analytic expression.

Weakly compressible approach
Another way to determine the density is based on the SPH smoothing operator itself. Therefore, the density is estimated from the particle distribution utilizing the SPH interpolation. To overcome undesired errors at the free surface through kernel truncation, the density formulation can again be integrated in time.

The weakly compressible SPH in fluid dynamics is based on the discretization of the Navier–Stokes equations or Euler equations for compressible fluids. To close the system, an appropriate equation of state is utilized to link pressure $$p$$ and density $$\rho$$. Generally, the so-called Cole equation (sometimes mistakenly referred to as the "Tait equation") is used in SPH. It reads

p = \frac{\rho_0c^2}{\gamma}\left(\left(\frac{\rho}{\rho_0}\right)^{\gamma}-1\right) + p_0 , $$

where $$\rho_0$$ is the reference density and $$c$$ the speed of sound. For water, $$\gamma = 7$$ is commonly used. The background pressure $$p_0$$ is added to avoid negative pressure values.

Real nearly incompressible fluids such as water are characterized by very high speeds of sound of the order $$10^3\mathrm{m/s}$$. Hence, pressure information travels fast compared to the actual bulk flow, which leads to very small Mach numbers $$M$$. The momentum equation leads to the following relation:

\frac{\delta\rho}{\rho_0}\approx\frac{|\boldsymbol{v}|^2}{c^2} = M^2 $$ where $$\rho$$ is the density change and $$v$$ the velocity vector. In practice a value of c smaller than the real one is adopted to avoid time steps too small in the time integration scheme. Generally a numerical speed of sound is adopted such that density variation smaller than 1% are allowed. This is the so-called weak-compressibility assumption. This corresponds to a Mach number smaller than 0.1, which implies:

c = 10v_\text{max} $$ where the maximum velocity $$v_\text{max}$$ needs to be estimated, for e.g. by Torricelli's law or an educated guess. Since only small density variations occur, a linear equation of state can be adopted:

p = c^2\left(\rho-\rho_0\right) $$

Usually the weakly-compressible schemes are affected by a high-frequency spurious noise on the pressure and density fields. This phenomenon is caused by the nonlinear interaction of acoustic waves and by fact that the scheme is explicit in time and centered in space .

Through the years, several techniques have been proposed to get rid of this problem. They can be classified in three different groups:
 * 1) the schemes that adopt density filters,
 * 2) the models that add a diffusive term in the continuity equation,
 * 3) the schemes that employ Riemann solvers to model the particle interaction.

Density filter technique
The schemes of the first group apply a filter directly on the density field to remove the spurious numerical noise. The most used filters are the MLS (moving least squares) and the Shepard filter which can be applied at each time step or every n time steps. The more frequent is the use of the filtering procedure, the more regular density and pressure fields are obtained. On the other hand, this leads to an increase of the computational costs. In long time simulations, the use of the filtering procedure may lead to the disruption of the hydrostatic pressure component and to an inconsistency between the global volume of fluid and the density field. Further, it does not ensure the enforcement of the dynamic free-surface boundary condition.

Diffusive term technique
A different way to smooth out the density and pressure field is to add a diffusive term inside the continuity equation (group 2) :

{\displaystyle {\frac {d\rho _{i}}{dt}}=\sum _{j}m_{j}\left({\boldsymbol {v}}_{i}-{\boldsymbol {v}}_{j}\right)\cdot \nabla W_{ij} + \mathcal{D}_i(\rho),} $$

The first schemes that adopted such an approach were described in Ferrari and in Molteni where the diffusive term was modeled as a Laplacian of the density field. A similar approach was also used in Fatehi and Manzari . In Antuono et al. a correction to the diffusive term of Molteni was proposed to remove some inconsistencies close to the free-surface. In this case the adopted diffusive term is equivalent to a high-order differential operator on the density field. The scheme is called δ-SPH and preserves all the conservation properties of the SPH without diffusion (e.g., linear and angular momenta, total energy, see ) along with a smooth and regular representation of the density and pressure fields.

In the third group there are those SPH schemes which employ numerical fluxes obtained through Riemann solvers to model the particle interactions.

Riemann solver technique

For an SPH method based on Riemann solvers, an inter-particle Riemann problem is constructed along a unit vector $$ \mathbf{e}_{ij} = - \mathbf{r}_{ij}/r_{ij} $$ pointing form particle $$ i $$ to particle $$ j $$. In this Riemann problem the initial left and right states are on particles $$ i $$ and $$ j $$, respectively. The $$ L $$ and $$ R $$ states are

$$ \begin{cases} (\rho_L, U_L, P_L) = (\rho_i, \mathbf{v}_i \cdot \mathbf{e}_{ij},P_i) \\ (\rho_R, U_R, P_R) = (\rho_j, \mathbf{v}_j \cdot \mathbf{e}_{ij},P_j). \end{cases} $$

The solution of the Riemann problem results in three waves emanating from the discontinuity. Two waves, which can be shock or rarefaction wave, traveling with the smallest or largest wave speed. The middle wave is always a contact discontinuity and separates two intermediate states, denoted by $$ (\rho_L^{\ast}, U_L^{\ast},P_L^{\ast}) $$ and $$ (\rho_R^{\ast}, U_R^{\ast},P_R^{\ast}) $$. By assuming that the intermediate state satisfies $$ U_L^{\ast} = U_R^{\ast} =U^{\ast} $$ and $$ P_L^{\ast} = P_R^{\ast} =P^{\ast} $$, a linearized Riemann solver for smooth flows or with only moderately strong shocks can be written as

$$ \begin{cases} U^{\ast} = \overline{U} + \frac{1}{2} \frac{(P_L - P_R)}{\bar{\rho} c_0}\\ P^{\ast} = \overline{P} + \frac{1}{2} \bar{\rho} c_0 {(U_L - U_R)} , \end{cases} $$

where $$ \overline{U} = (U_L + U_R)/2 $$ and $$ \overline{P} = (P_L + P_R)/2 $$ are inter-particle averages. With the solution of the Riemann problem, i.e. $$ U^{\ast} $$ and $$ P^{\ast} $$, the discretization of the SPH method is

$$\frac{d \rho_i}{d t} = 2 \rho_i \sum_j \frac{m_j}{\rho_j} (\mathbf{v}_i - \mathbf{v}^{\ast})\cdot \nabla_{i} W_{ij}, $$

$$\frac{d \mathbf{v}_i}{d t} = - 2\sum_j m_j \left( \frac{ P^{\ast}}{\rho_i \rho_j} \right) \nabla_i W_{ij}.$$

where $$ \mathbf{v}^{\ast} = U^{\ast} \mathbf{e}_{ij} + ( \overline{\mathbf{v}}_{ij} - \overline{U}\mathbf{e}_{ij} ) $$. This indicates that the inter-particle average velocity and pressure are simply replaced by the solution of the Riemann problem. By comparing both it can be seen that the intermediate velocity and pressure from the inter-particle averages amount to implicit dissipation, i.e. density regularization and numerical viscosity, respectively.

Since the above discretization is very dissipative a straightforward modification is to apply a limiter to decrease the implicit numerical dissipations introduced by limiting the intermediate pressure by

$$ P^{\ast} = \overline{P} + \frac{1}{2} \beta \overline{\rho} {(U_L - U_R)}, $$

where the limiter is defined as

$$\beta = \min\big( \eta \max(U_L - U_R, 0), \overline{c} \big).$$

Note that $$ \beta $$ ensures that there is no dissipation when the fluid is under the action of an expansion wave, i.e. $$ U_L < U_R $$, and that the parameter $$\eta $$, is used to modulate dissipation when the fluid is under the action of a compression wave, i.e. $$ U_L \geq U_R $$. Numerical experiments found the $$ \eta = 3 $$ is generally effective. Also note that the dissipation introduced by the intermediate velocity is not limited.

Viscosity modelling
In general, the description of hydrodynamic flows require a convenient treatment of diffusive processes to model the viscosity in the Navier–Stokes equations. It needs special consideration because it involves the Laplacian differential operator. Since the direct computation does not provide satisfactory results, several approaches to model the diffusion have been proposed.

Introduced by Monaghan and Gingold the artificial viscosity was used to deal with high Mach number fluid flows. It reads
 * Artificial viscosity

\Pi _{ij} = \begin{cases} \dfrac{-\alpha \bar{c}_{ij} \phi_{ij} + \beta \phi^2_{ij}}{\bar{\rho}_{ij}} & \quad \boldsymbol{v}_{ij} \cdot \boldsymbol{r}_{ij} < 0\\ 0   & \quad \boldsymbol{v}_{ij} \cdot \boldsymbol{r}_{ij} \geq 0 \end{cases} $$ Here, $$ \alpha$$ is controlling a volume viscosity while $$ \beta $$ acts similar to the Neumann Richtmeyr artificial viscosity. The $$ \phi_{ij} $$ is defined by

\phi_{ij} = \frac{h\boldsymbol{v}_{ij}\cdot \boldsymbol{r}_{ij}}{\Vert \boldsymbol{r}_{ij} \Vert^2 + \eta_h^2}, $$ where ηh is a small fraction of h (e.g. 0.01h) to prevent possible numerical infinities at close distances.

The artificial viscosity also has shown to improve the overall stability of general flow simulations. Therefore, it is applied to inviscid problems in the following form

\Pi_{ij} = \alpha h c \frac{\boldsymbol{v}_{ij} \cdot \boldsymbol{r}_{ij}}{\Vert \boldsymbol{r}_{ij} \Vert^2 +\eta_h^2 }. $$ It is possible to not only stabilize inviscid simulations but also to model the physical viscosity by this approach. To do so

\alpha h c = 2(n+2) \frac{\mu}{\rho} $$ is substituted in the equation above, where $$ n $$ is the number of spatial dimensions of the model. This approach introduces the bulk viscosity $$ \zeta = \frac{5}{3} \mu $$.

 * Morris

For low Reynolds numbers the viscosity model by Morris was proposed.

[\nu \Delta \boldsymbol{v}]_{ij} = 2\nu \frac{ m_j}{\rho_j} \,\frac{\boldsymbol{r}_{ij} \cdot \nabla w_{h,ij}}{\Vert \boldsymbol{r}_{ij} \Vert ^2 +\eta_h^2} \, \boldsymbol{v}_{ij}. $$

 * LoShao

Additional physics

 * Surface tension
 * Heat transfer
 * Turbulence

Astrophysics
Often in astrophysics, one wishes to model self-gravity in addition to pure hydrodynamics. The particle-based nature of SPH makes it ideal to combine with a particle-based gravity solver, for instance tree gravity code, particle mesh, or particle-particle particle-mesh.

Total Lagrangian formulation for solid mechanics
To discretize the governing equations of solid dynamics, a correction matrix $$ \mathbb{B}^0 $$ is first introduced to reproducing rigid-body rotation as

where

$$ \nabla_a^0 W_{a} = \frac{\partial W\left( |\mathbf{r}_{ab}^0|, h \right)} {\partial |\mathbf{r}_{ab}^0|} \mathbf{e}_{ab}^0 $$

stands for the gradient of the kernel function evaluated at the initial reference configuration. Note that subscripts $$ a $$ and $$ b $$ are used to denote solid particles, and smoothing length $$ h $$ is identical to that in the discretization of fluid equations.

Using the initial configuration as the reference, the solid density is directly evaluated as

where $$ J = \det(\mathbb{F}) $$ is the Jacobian determinant of deformation tensor $$ \mathbb{F} $$.

We can now discretize the momentum equation in the following form

where inter-particle averaged first Piola-Kirchhoff stress $$ \tilde{\mathbb{P}} $$ is defined as

Also $$ \mathbf{f}_a^{F:p} $$ and $$ \mathbf{f}_a^{F:v} $$ correspond to the fluid pressure and viscous forces acting on the solid particle $$ a $$, respectively.

Fluid-structure coupling
In fluid-structure coupling, the surrounding solid structure is behaving as a moving boundary for fluid, and the no-slip boundary condition is imposed at the fluid-structure interface. The interaction forces $$ \mathbf{f}_i^{S:p} $$ and $$ \mathbf{f}_i^{S:v} $$ acting on a fluid particle $$ i $$, due to the presence of the neighboring solid particle $$ a $$, can be obtained as

and

Here, the imaginary pressure $$ p_a^d $$ and velocity $$ \mathbf{v}_a^d $$ are defined by

where $$ \mathbf{n}^S $$ denotes the surface normal direction of the solid structure, and the imaginary particle density $$ \rho_a^d $$ is calculated through the equation of state.

Accordingly, the interaction forces $$ \mathbf{f}_a^{F:p} $$ and $$ \mathbf{f}_a^{F:v} $$ acting on a solid particle $$ a $$ are given by

and

The anti-symmetric property of the derivative of the kernel function will ensure the momentum conservation for each pair of interacting particles $$ i $$ and $$ a $$.

Others
The discrete element method, used for simulating granular materials, is related to SPH.

Software

 * Algodoo is a 2D simulation framework for education using SPH
 * AQUAgpusph is the free (GPLv3) SPH of the researchers, by the researchers, for the researchers
 * dive solutions is a commercial web-based SPH engineering software for CFD purposes
 * DualSPHysics is a mostly open source SPH code based on SPHysics and using GPU computing. The open source components are available under the LGPL.
 * FLUIDS v.1 is a simple, open source (Zlib), real-time 3D SPH implementation in C++ for liquids for CPU and GPU.
 * Fluidix is a GPU-based particle simulation API available from OneZero Software
 * GADGET is a freely available (GPL) code for cosmological N-body/SPH simulations
 * GPUSPH SPH simulator with viscosity (GPLv3)
 * Pasimodo is a program package for particle-based simulation methods, e.g. SPH
 * LAMMPS is a massively parallel, open-source classical molecular dynamics code that can perform SPH simulations
 * Physics Abstraction Layer is an open source abstraction system that supports real time physics engines with SPH support
 * PreonLab is a commercial engineering software developed by FIFTY2 Technology implementing an implicit SPH method
 * Punto is a freely available visualisation tool for particle simulations
 * pysph Open Source Framework for Smoothed Particle Hydrodynamics in Python (New BSD License)
 * Py-SPHViewer Open Source python visualisation tool for Smoothed Particle Hydrodynamics simulations.
 * RealFlow Commercial SPH solver for the cinema industry.
 * RheoCube is a commercial SaaS product by Lorenz Research for the study and prediction of complex-fluid rheology and stability
 * SimPARTIX is a commercial simulation package for SPH and Discrete element method (DEM) simulations from Fraunhofer IWM
 * SPH-flow
 * SPHERA
 * SPHinXsys is an open source multi-physics, multi-resolution SPH library. It provides C++ APIs for physical accurate simulation and aims to model coupled industrial dynamic systems including fluid, solid, multi-body dynamics and beyond.
 * SPHysics is an open source SPH implementation in Fortran
 * SPLASH is an open source (GPL) visualisation tool for SPH simulations
 * SYMPLER: A freeware SYMbolic ParticLE simulatoR from the University of Freiburg.
 * Nauticle is a general-purpose computational tool for particle-based numerical methods.
 * NDYNAMICS is a commercial fluid simulation software based on implicit SPH developed by CENTROID LAB currently used for internal/external flooding/nuclear/chemical engineering applications.

title: Smoothed-particle hydrodynamics


text:
Blödite

Blödite or bloedite is a hydrated sodium magnesium sulfate mineral with the formula Na2Mg(SO4)2·4H2O. The mineral is clear to yellow in color often darkened by inclusions and forms monoclinic crystals.

Blödite was first described in 1821 for an occurrence in a salt deposit in Ischler Salzberg, Bad Ischl, Gmunden, Austria and named for German mineralogist and chemist Karl August Blöde (1773–1820).

It is found worldwide in evaporitic sedimentary environments such as the Great Salt Lake, Utah.

title: Blödite


text:
Talk:Pingu

Revival
According to the NHK news here:http://www6.nhk.or.jp/nhkpr/post/original.html?i=11509 Pingu will return as part of the new CGI series Pingu in the City.

Untitled
Is there any truth in the rumour that all the dialogue was highly sped-up and/or backwards dutch/swiss swearing?
 * No. --HappyDog 17:16, 19 Dec 2004 (UTC)

"Smack the pingu"?
Is the link to a game called "Smack the pingu" really relevant to the article? There's nothing but the name (and the species of the animal involved) that links it with the TV series. --EldKatt 16:04, 22 Jun 2005 (UTC)

The Igloos
The article says Pingu's family lives in an igloo formerly inhabited by Inuit. Are you sure about that? I always had the impression that in this story, penguins build the igloos themselves. There's even an episode where Pingu goes camping with his friend and they make their own igloo. --Mithcoriel 19:34, 29 August 2006 (UTC)

I agree. It's a little dubious. If it's still there, it should be removed.

 * I think it meant 'the type of dwelling inhabited by inuits in former times' and is just a badly worded sentence. Have fixed it. --HappyDog 20:11, 20 November 2006 (UTC)

Am I the only one who thinks that "Pingu 3 - Hide and Seek" (BBCV 4868) deserves a "PG" rating?
And surely the words "charming" and "lovable" on the front cover shouldn't be there? For some reason seeing Pingu, Robby and Pinga covered in hideous blue paint with equally hideous false faces over their own made me feel really sick, and has put me off watching Pingu again forever. They looked really scary and evil!!! Namcorules 13:07, 1 March 2007 (UTC)

it is for kids, but there is other wierd episodes like that, in one the whole episode is pingu drinks too much and accidently urinates on the bathroom floor, (after his sister urinated in the shop and after pingu had tried to steal the potty of his sister AND after he tricked his dad out of the toilet)another wierd one is where pingu has a bad dream about objects in his house floating away, his bed walking, and a giant sea lion that harrass's pingu, then again, its for 4 year olds

To be accurate, it is actually the episode "Pingu Plays Circus" that you were probably referring to not "Hide and Seek" (according to the summary). However, in the "Hide and Seek" episode, the fact of Pingu putting a bust of his head on a stick would suggest that differently (as it is kind of startling, as it looks like he got beheaded, it has prevented me from watching that epiosde). trainfan01 talk 18:36, January 11, 2011 (UTC)

ahh
i love Pingu...or at least i did.

Dance version
The dance version of the theme was used when the ABC (Australian Broadcasting Corporation) used to air Pingu. — Jeremy  23:56, 7 October 2007 (UTC)

Huge and pressing question
All right, once and for all: is it "Pinguish" or "Penguinese"? Which are we going to use as the main name of the language in the article? We can't be switching back and forth from sentence to sentence. I support "Pinguish" myself--more Google hits for that than for "Penguinese"--but we need a consensus here. Please respond. Gladys J Cortez 00:12, 4 February 2008 (UTC)
 * Pingu facts No.2 on the "official" site says that it is Penguinese! Kwerty (talk) 03:17, 26 February 2008 (UTC)

Road Signs
I noticed that when Pingu and Pingi parted company after first meeting at school, it looked very much like the sign said "glasnost" in one direction, and "perestroika" in this other. Is it me? has anyone else noticed interesting content like that? Philculmer (talk) 16:42, 30 April 2008 (UTC)
 * You're probably right (the synopsis for this episode (episode 2.2) has had a footnote to this effect for some time). Good work, though. If you come across further oddities they could be highlighted in similar fashion, as I'm sure there are more to be found. A browse through the current synopses will give you some idea of what's already been spotted! Kwerty (talk) 01:58, 7 May 2008 (UTC)

Contoversy - Madonna, etc.
Does Madonna's opinion on this show really belong here? If you really want a "controversy" on here, this one would be better: Cute Cartoon Character Causes Controversy Hill of Beans (talk) 22:30, 16 June 2008 (UTC)

Episode series articles need re-writing
Hello. I've noticed that the articles for each episode series 1-6 are written in an un-professional way, with inappropriate tone and such. I suggest they need re-writing so that they appear in an appropriate tone for Wikipedia. —Preceding unsigned comment added by 68.121.110.213 (talk) 02:45, 28 December 2008 (UTC)
 * Can you be more specific, please, as there are 156 episodes in the 6 series and I can't believe that they're all problematic!? I would agree that Series 1 needs some attention / tidying up, to be more consistent with the style of the synopses in the other 5 series, but I don't think there's much wrong with most of the others. After looking at the Wiki help on writing articles, I admit I'm not at all sure what the correct "professional way" might be. Kwerty (talk) 21:16, 31 December 2008 (UTC)
 * In the absence of any comments, I assume that any "style" changes are not thought to be necessary, so I'll be removing the "warning" soon.Kwerty (talk) 04:29, 24 January 2009 (UTC)
 * Going, going, .... Kwerty (talk) 15:58, 16 February 2009 (UTC)

History
While "cute", the first sentence of the history has a different tone than the rest of the article. I should also remark that the article is about the TV series and not the character. And also I'm not entirely sure if referring to the character as if it were a living creature is an adequated writing style for the Wikipedia. I will hence revert the article to the previous state, before Potato114's edition. Damianvila (talk) 10:46, 15 July 2009 (UTC)

Technicially, this article is about the character as well as the TV series (since he is not notable enough for a seperate article), but yes I agree about that paragraph after looking back at it through edit histories. trainfan01 talk 18:55, March 26, 2011 (UTC)

Source suggests location of trickfilmstudio in Switzerland
I think they are at www.swamp.ch now which has an address in Lucerne

but this page says that a modelmaker worked on Pingu in Russikon http://www.trance-parent.ch/index_03.html

--LeedsKing (talk) 23:30, 25 August 2009 (UTC)

Original run confusing
It seems to say that it ran on 1986, than on 2004 up to 1998, and had a stint in 2005. The location of the numbers and the use of commas is confusing. Don't know how to change that - any ideas? Thanks, Arie. --93.172.95.2 (talk) 01:28, 13 February 2010 (UTC)
 * It seems to be better now.

Songs
I noticed in the episode lists it says a bunch of songs that weren't even featured in the episode. and this is probably a teen or someone doing all this. Because in Pingu at the Doctors, it says "Another short that featured blood was a short called 'Mirror'." Can someone report his account or something? —Preceding unsigned comment added by 76.188.40.229 (talk) 23:43, 13 May 2010 (UTC)

Death of Pingu?
Did pingu die, or has this page been defaced? 82.109.87.242 (talk) 11:47, 15 April 2010 (UTC)

I do not remember seeing an episode where Pingu dies. I think it's vandalism, especially seeing as it is also mentioned that in the last episode Robbie dies of a heart attack, something that I think is almost certainly untrue and too dark for a show like this. fsdfsd (talk) 14:40, 16 April 2010 (UTC) —Preceding unsigned comment added by Notsoboxy (talk • contribs) 14:38, 16 April 2010 (UTC)

Pingu's Dream
It aired costantly in Italy. It was actually one of my favourites when I was a kid, despite being so creepy. It was banned in some countries, but not Italy, apparently. That statement has to be checked, imho —Preceding unsigned comment added by 82.56.126.52 (talk) 00:30, 27 June 2010 (UTC)

Pingu's Dream
It aired costantly in Italy. It was actually one of my favourites when I was a kid, despite being so creepy. It was banned in some countries, but not Italy, apparently. That statement has to be checked, imho —Preceding unsigned comment added by 82.56.126.52 (talk) 00:31, 27 June 2010 (UTC)

Okay
Stop it, I seen Pingu's dream in the US. Stop saying it's been banned in every country but Japan and North Korea. 68.89.1.181 (talk) 05:49, 26 October 2010 (UTC)

Channels
Everybody keeps saying Pingu aired on either BBC 2 or RTSI. But on the HiT Entertainment website it says "SF DRS." I keep trying to change it to that, but everybody is changing it back, without making sure that that's the channel it was on. I do know, however, that they did send the pilot episode to RTSI, but RTSI didn't pick it up. And on the Pingu article (series 5), in "Pingu Stick up", it says "Stuck On You - Paramore", and after that it says "OMGRLY? FBJFHFGHFFF!" It's making me kind of annoyed. Everybody's messing with all the Pingu articles lately, too. —Preceding unsigned comment added by Potato114 (talk • contribs) 22:14, 1 December 2010 (UTC)

German reference
I found out "der Pinguin" is German for penguin. I think Pingu was named after the first five letters of the word. If there are issues, ask away. —Preceding unsigned comment added by 24.24.187.165 (talk) 16:37, 22 May 2011 (UTC)

ORLY? INFLATABLE CHAIRRR?
Okay, someone keeps messing with all the Pingu articles and I wanna know who. Claymation errors are not characters. Also, stuff is happening to the Pingu wiki too with vandalism. Could it be the same person? Just maybe the Pingu wiki doesn't have as much security? — Preceding unsigned comment added by 65.24.89.242 (talk) 03:44, 24 February 2012 (UTC)

WANTED!
Listen up. There's a vandal named GiantSnowman who has deliberately deleted the article on series 1 for no apparent reason. Anyone reading this message must have this vandal banned and the series 1 article restored! Repeat: GiantSnowman is at large, be on the lookout! Visokor (talk) 07:30, 24 August 2013 (UTC)

Question
Is this the series which inspired the Longman ELT course "Pingu Loves English" or is it the other way around, the course inspired the series? Or is it even the video component of said course? --Marce 22:50, 25 June 2014 (UTC) — Preceding unsigned comment added by Fandelasketchup (talk • contribs)
 * I think the series inspired the course. Series was introduced in the 1980's and the course was published in 2001. But I'm not entirely sure. --Mr. Guye (talk) 01:43, 11 March 2015 (UTC)

Bring the episode list articles back!
Hey! Bring back the episode list articles! They have as much right to be on Wikipedia as other episode list articles do! Visokor (talk) 18:40, 13 August 2015 (UTC)

External links modified
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 * Corrected formatting/usage for http://www.kcl.ac.uk/content/1/c6/03/08/18/Pingu%27s%20Lingo%2C%20or%20How%20to%20Get%20By%20in%20Penguinese.doc

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Semi-protected edit request on 23 August 2017
"Pingu Quarrels with his Mom" should be "Pingu Quarrels with his Mother". Freddiefredoes (talk) 14:22, 23 August 2017 (UTC)
 * Yes check.svg Done DRAGON BOOSTER   ★  15:05, 23 August 2017 (UTC)
 * A quick Google search leads me to believe that it should actually be "Pingu Quarrels With His Mum". Would you be so kind to supply a reliable source for your claim?  Lordtobi  ( ✉ ) 15:14, 23 August 2017 (UTC)

Production years
The production years are messed up. It says 1990 in the article, then later it says the show aired in India in the late 80s. Official begin of production was to my knowledge 1986. 77.178.171.6 (talk) 10:50, 16 July 2018 (UTC)
 * 1986 is apparently correct, so I've gone ahead and changed all occurrences of the start date to that. -- Pingumeister(talk) 22:28, 6 June 2019 (UTC)

Dates are confusing!!
How can the series run from 1990 but the first episode air in 1986?! I cannot see any info to substantiate the 1986 date?? (user tqfan, not logged in) 86.26.82.0 (talk) 15:24, 6 June 2019 (UTC)
 * 1986 is apparently correct, so I've gone ahead and changed all occurrences of the start date to that. -- Pingumeister(talk) 22:28, 6 June 2019 (UTC)

Production dates, again
Where are the sources for these dates (1990 and onwards)? IMDb states that the series was first aired in 1986. I cannot find any official information regarding dates. -- Pingumeister(talk) 07:53, 25 July 2019 (UTC)

Rephrasing part of "Production history"
"These episodes were animated through stop motion like the original, but used resin casts of the original clay puppets (which had deteriorated by this time)."

This can be rather confusing to several people. People may wonder, "Have the resin casts deteriorated since this was put in?" "Did the clay puppets deteriorate before the casts were made?"

And I would like to help clear this up.

According to a Guardian article from 2016, Steve Cox (an animator for Aardman, also worked with HOT Animation) gathered the materials from the original filmstudio and had seen that the original clay puppets had deteriorated. Later on was when they were recast with resin.

So I think a better way to put this would be "These episodes also used stop motion like the original, but the original clay puppets (which had deteriorated around that time) were recast with resin. Unlike the original series, the new series used Replacement Animation instead of traditional clay animation."

Adjust if needed. Thank you.

K24a1.4300i (talk) 23:01, 18 December 2020 (UTC)

Pinga and Pingi
Pingi isn't Pinga's best friend. They never interacted with eachother

--73.15.231.170 (talk) 00:41, 30 January 2021 (UTC)

title: Talk:Pingu