Talk:Wingtip vortices

article inconsistancy

The article states that: "Fluids naturally flow from low to high pressure and the relatively high pressure air below the wing has a natural tendancy to flow to the top of the wing." Isn't the one sentence contrary to the other? I was wondering which is true! Does air flow from low to high pressure or the opposite?

Thanks for finding that mistake! I've changed the article with the correct info (they flow from high to low pressure). -Lommer | ^talk 03:37, 25 Jan 2005 (UTC)

Merge proposal

Wingtip vortices and wake turbulence are distinct enough phenomena in my (currently winding down an advanced fluid mechanics course) opinion that they deserve discrete articles.

I agree, the reason I put up the merge tag is that theres a lot of info in wake turbulence that is duplicated here, and there's a lot that belongs here and not there. The wake tubulence article should still exist, but it doesn't need to cover wingtip vortices in detail; that's what this article is for. -Lommer | ^talk 23:47, 21 August 2005 (UTC)

I've undone a poor attempt at a merge that resulted in something even worse. I've maintained the wake turb-only aspects at that page, and removed duplicated information and wintip-vortex-specific info to here. -Lommer | ^talk 23:31, 31 October 2005 (UTC)

misleading statement about proportionality

"Since the size and power of wingtip vortices are directly proportional to the size and speed of an aircraft..." ...better write proportional to V^2 instead of speed (cause Lift~bound circulation and lift ~V^2 and trailing circulation is deviation of bound circulation and for this article it should be assumed that all trailing circulation is rolled up into wingtip vortices)for those who are not common with aerodynamics

Misplaced Picture

Regarding the picture entitled "F/A-18F showing vapor cloud over its wings".

Although this is a fascinating picture it doses not show any formation of tip vortices. It does however illustrate that lift is produced by low pressure on the wing top with can be seen in certain atmospheric conditions. I therefore suggest it is moved to the section describing lift.

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 10:06, 10 November 2007 (UTC)

Regarding Title Picture

The description for the F15E picture is rather misleading, the picture more accurately depict aerodynamic condensation trails. —Preceding unsigned comment added by 76.91.58.173 (talk) 19:27, 26 May 2008 (UTC)

Merge with Starting vortex

On 20 August 2008, De728631 proposed merging Wingtip vortices and Starting vortex. I am opposed to such a merger - the two articles have little in common and rely on separate references. Wingtip vortices are a real phenomenon, contributing to wake turbulence and regularly visible as streams of condensed moisture. On the contrary, the concepts of Starting vortex and Horseshoe vortex are important elements in the Circulation theory of lift. Starting vortices can rarely, if ever, be observed without the aid of special equipment. The horseshoe vortex never exists as an observable phenomenon - it is a mathematical simplification to assist in application of Helmholtz's theorems and the Circulation theory of lift. Leave the existing articles as they are. Dolphin51 (talk) 11:49, 27 August 2008 (UTC)

That's a good point. On the first look, the two topics seemed related to me, but your explanation convinced me. Let's leave the two articles separated. De728631 (talk) 21:31, 27 August 2008 (UTC)

Photo gallery

On 12 October 2008, Atmoz deleted the photo gallery from Wingtip vortices, saying there were too many photographs, and only one of them actually showed wingtip vortices.

I reverted the edit to restore the photo gallery. Whether there are too many photographs in the gallery, or not enough, or just the right number, is something best determined by Users who read and contribute to Wingtip vortices. I would appreciate others adding their comments.

My view is that whether a photograph adds value to the article depends on the quality and relevance of the photograph. I see no case for saying there is an ideal number of photographs; and therefore no case for saying there are too many.

It is true that one or two of the photographs show visible cores trailing from points on the wing other than the wingtip. The expression trailing vortices is commonly used in aviation literature and some of the photographs show the cores of trailing vortices (for example, from the outboard end of the wing flap) rather than wingtip vortices. In Wikipedia, the expression trailing vortices redirects to wingtip vortices.

Do other Users feel there are too many photographs? Dolphin51 (talk) 11:02, 12 October 2008 (UTC)

I removed them per WP:NOTREPOSITORY. Most of them show condensation trails anyway, and not vortices, as you note. - Atmoz (talk) 16:34, 12 October 2008 (UTC)

Correction

Updated the article to point out that the strongest vortices are generated in a clean configuration, not one with flap extended. This is because extending the flaps increases the coefficient of lift, decreasing the angle of attack and hence reducing the intensity of the vortices.

--Dave. —Preceding unsigned comment added by 92.1.142.56 (talk) 20:40, 9 December 2008 (UTC)

Dave, I disagree. For a given aircraft weight, load factor, wing area and airspeed there is a single value of aircraft lift coefficient, regardless of flap setting. (If the flaps are Fowler flaps they increase the wing area as they extend, and consequently extending the flaps causes the aircraft lift coefficient to decrease.) I agree that extending the flaps causes the angle of attack to decrease (thereby protecting the wing tips from stalling, and promoting root stall.)

The core of the vortex trailing from the tip of the flap. No similar vortex core visible trailing from the wing tip.

The intensity of the vortices is strongly dependent on spanwise lift distribution. Extending the flaps causes a major disruption to the spanwise lift distribution at the outboard end of the flaps. That is why an aircraft taking off or landing in humid conditions will often have visible vortex cores trailing from the outboard end of the flaps but none from the actual wingtips.

The vortices are strongest when induced drag is a maximum. If it is true that the strongest vortices are generated in a clean configuration, it would be possible to reduce induced drag by extending the flaps, thereby reducing the strength of the vortices. We know that induced drag is greater with flaps extended than in the clean configuration.

Dave, if you still believe that your recent amendment is correct, please provide a citation to point to the source of your information. Dolphin51 (talk) 03:22, 10 December 2008 (UTC)

You're quite right, I was wrong in my argument. My understanding is that lowering the flaps significantly impacts the spanwise flow on the top of the wing, effectively increasing the aspect ratio and hence reducing the strength of the wingtip vortices.

I'm going to have to go off dig the correct definition out of a book, since a quick internet search has actually revealed that not only is my understanding flawed, but there are differing opinions on wingtip vortices in general. —Preceding unsigned comment added by 92.0.205.200 (talk) 16:31, 11 December 2008 (UTC)

I have reversed your change. Hopefully it is now OK. Extending partial-span flaps certainly has an impact on the spanwise flow on the top of the wing, but it has the effect of decreasing the aspect ratio because of the greater chord for the same span. Induced drag increases and the wingtip vortices increase in strength. This is actually beneficial in the landing maneuver when plenty of drag is required, but it is a disadvantage in takeoff. That is why only a small amount of flap is used for takeoff, but a much greater amount is used for landing. Dolphin51 (talk) 01:46, 24 February 2009 (UTC)

Wingtip vortices - Prevention.

Just out of curiosity, was the A380 wingtip designed to prevent vortices and increase lift from a smaller wing plan. On each of their profile sides they seem to have a mini 'winglet' for this. Just a thought that might be worth investigating. Does anyone know what effect it would have on proceeding aircraft, if any? 77.100.16.146 (talk) 20:50, 28 February 2009 (UTC)

i dunno how to mail this Polypuss (talk) 22:18, 18 April 2009 (UTC) More corrections! The apex bird experiences exactly the same drag saving from his two wingmen as any other in the Vee. See Lissaman & Shollenberger, Nature 1969. Fluids flow into and out of low pressure and high pressure regions! How could they do otherwise, with continuity!! Consider a convergent-divergent nozzle!! Vortex strength has nothing to do with induced drag . It is given simply by L = rUGb, where L is the lift, r the density, U flight speed , G vortex strength and b the effective span. For flaps the effective span is less than the actual. —Preceding unsigned comment added by Polypuss (talk • contribs) 03:43, 19 April 2009 (UTC)

Confusing statement

The third paragraph in the [1] section states two contradicting things. the first statement says that the melting point of water decreases with rising pressure while the next statement apparently states the opposite. Please rectify. --Sungolf (talk) 02:53, 22 August 2009 (UTC)

Done; I hope it's O.K. now. Reuqr (talk) 02:41, 24 September 2009 (UTC)

decreases Max turbulence anywhere on the wing

Increase in flaps results in increase in wing surface and decrease in load /surface ratio lbs/sqft. This decreases the Max Pressure gradient on any edge and therefore decreases Max turbulence anywhere on the wing .Wdl1961 (talk) 01:01, 26 October 2009 (UTC)

Plural title should be singular, per WP:PLURAL

Wikipedia:Naming conventions (plurals) seems to indicate that the article title Wingtip vortices should properly be Wingtip vortex. However, Wingtip vortex already exists as a redirect to Wingtip vortices. WP:PLURAL suggests the relationship should be the other way around: Wingtip vortices should be a redirect to Wingtip vortex. Only an administrator can correct this problem since the existing redirect is blocking the required move. --Teratornis (talk) 19:48, 6 August 2011 (UTC)

Section on the visibility of vortices through water condensation

There’s a long section now titled Discussion of the physics of aerodynamic condensation and freezing that I believe should be deleted. It certainly is an interesting read (it sounds like an exciting, enthusiastic lecture transcript) but I see two problems:

1. The tone is not that of an encyclopedia article (it makes me think of a textbook or physics magazine article)
2. It is off-topic, i.e. it would be better suited to an article on "Aerodynamic condensation and freezing" (once re-written for tone).

For these reasons I believe it should be deleted. Can anyone think of a place where it could be moved, such as the Wikiversity or a wikibook? Thanks, Ariadacapo (talk) 07:15, 5 September 2012 (UTC)

Seems to have been added by User:Reuqr. [2] Wizzy…☎ 08:43, 5 September 2012 (UTC)

Thanks for pointing it out! (I have pinged him/her). Out of curiosity, do you have a specific method for attributing pieces of articles, or do you browse large chunks of history until the edit appears/disappears? Ariadacapo (talk) 19:09, 7 September 2012 (UTC)

The 'large chunk' thing - I go back until its not there and then bisect chunks of history. Wizzy…☎ 23:30, 8 September 2012 (UTC)

Thank you Ariadacapo for alerting me to this proposed change. I'm certainly OK with any stylistic rewrites that do not substantially reduce content or clarity. I'm also certainly OK with moving the section to any other appropriate WP article, as long as the wingtip vortices article links, at the appropriate place (and not, say, under "See also"), to the appropriate section of that new article, with some explanation of why the link is there (i.e. what is the topic of the text to which the link points). Reuqr (talk) 15:16, 15 September 2012 (UTC)

Don't know if any rewrites have occurred, as the section still reads 'textbooky'. I have however renamed the section from "Discussion of the physics of aerodynamic condensation and freezing" to the shorter "Aerodynamic condensation and freezing". And the NASA source is a deadlink, fortunately only used once. --220 of ^Borg 07:50, 29 May 2014 (UTC)

No rewrites have taken place. I still am convinced that most of the text there should be deleted. If anyone gets started, I’ll happily chip in. Ariadacapo (talk) 18:58, 31 May 2014 (UTC)

wingtip vortices - explanation - prevention?!

there are two essential statements that need better explanation for those who are not already experts (experts who tend to be into esoteric insider-talk...):

"The rotary motion of the air within the shed wingtip vortices ... reduces the effective angle of attack of the air on the wing." why and how?

"For a given lift distribution and surface, induced drag is reduced with increasing aspect ratio." why and how?

please explain these phenomena also in non-mathematical terms and use pictures. an attempt in this sense is made f.i. here: http://www.youtube.com/watch?v=Dhlt1fsnhVE&list=PLzOZJYQgMpB9Myp1zOMMu7sntxQS8k1OS&index=64 (first quarter) - but it remains unclear... ("...will spread its [the lift's] influence over more air [?] resulting in lower pressure..." - you can reduce pressure by making the surface lager onto which a certain force acts; but this does not happen...)

thanx! --HilmarHansWerner (talk) 22:15, 5 February 2013 (UTC)

HilmarHansWerner - I agree that the article does not explain this sufficiently well.

However, the very title/topic of the article, focusing on the wingtip, prevents from covering the topic precisely. You may want to have a look at Horseshoe vortex and Lifting-line theory which deal with it better. In short, although vorticity is most visible at the wingtip it is trailed anywhere there is a change in lift distribution on the wing. It’s a "self-redefining" problem where the lift distribution (the "effect of the vortices on the angle of attack") depends on itself. You need an integro-differential equation to describe this.

So, I’m not too hopeful that we can manage an accessible explanation... Ariadacapo (talk) 14:47, 6 February 2013 (UTC)

External links modified

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Removal of 'copyrighted' content

I don't know about the rest of the content that was removed, but the text I originally contributed in 2009 (which concerned thermodynamics of condensation within a vortex) was entirely my own, with references to reputable sources. What appears on https://jazzroc.wordpress.com/tag/vortex/ (I'll be linking to a 2016 snapshot of that page) is an (almost) blanket copy of at least that part of the text, without attribution to this Wikipedia page. (The text does acknowledge en.wikipedia.org/wiki/Vortices, but not the present page.)

Yes, the date on https://jazzroc.wordpress.com/tag/vortex/ page claims to be 2008, so before my 2009 edit, but all I can say is that this is not correct.

Unfortunately, the snapshots on the Internet Archive don't go back far enough to enable any simple comparison that would clearly show that what I'm saying is true.

However, here is one dead giveaway that supports my claim. If you look at this snapshot of the Wikipedia page from Nov 2009, you will see that the part of the text that the concerns thermodynamics says, right before the first equation,

Here we follow the discussion in Ref. [2].

That reference is Green, S. I. "Wing tip vortices" in Fluid vortices, S. I. Green, ed. (Kluwer, Amsterdam, 1995) pp. 427-470. ISBN 978-0792333760.

If you look at https://jazzroc.wordpress.com/tag/vortex/, that sentence has been removed, and the reference in question is not mentioned anywhere.

But if you have any doubt that the discussion in fact did come from that book, take a look at this page from that book. When I was writing the Wikipedia text, I slightly changed the temperature of the environment, from 290 K in the book to 20 °C = 68 °F = 293.15 K, because it's a familiar round number in both degrees Celsius and degrees Fahrenheit.

In short, at least as far as the section on thermodynamics, it is https://jazzroc.wordpress.com/tag/vortex/ that has plagiarized Wikipedia!

--Reuqr (talk) 10:46, 9 April 2021 (UTC)

This is indeed a backwards copy - one of the very few cases where the date on the source is misleading and the tone of the inserted text is suspicious. I've restored the contentMER-C 16:44, 9 April 2021 (UTC)

Thank you, MER-C. --Reuqr (talk) 00:01, 10 April 2021 (UTC)

"Effects and mitigation" requires clarity

"Another method of reducing induced drag is the use of winglets, as seen on most modern airliners. Winglets increase the effective aspect ratio of the wing, changing the pattern and magnitude of the vorticity in the vortex pattern. A reduction is achieved in the kinetic energy in the circular air flow, which reduces the amount of fuel expended to perform work upon the spinning air."

My understanding is that induced drag causes the vortices, so why would "changing the pattern and magnitude of the vorticity in the vortex pattern" result in a drop in induced drag? The paragraph could be expanded for clarity. FropFrop (talk) 04:54, 7 June 2023 (UTC)

I agree that some extra clarity would be desirable. However, your understanding that “induced drag causes the vortices” is immature. This style of thinking about matters of physics is highly inaccurate. When an airfoil is inclined to a flowing fluid so that it has an angle of attack, many things happen - lift occurs, drag increases, the fluid velocity around the airfoil acquires a spanwise component, a vortex sheet develops, trailing vortices develop, downwash occurs, orientation of the lift and drag vectors changes, lift-induced drag occurs, and so on! There are other changes too, that I haven’t mentioned. To select one of these (such as induced drag) and suggest that it causes one of the others (such as trailing vortices) is incorrect. All these things occur simultaneously as a consequence of changing the angle of attack on the airfoil. There is no other cause-and-effect, and there is no time lag between them as is sometimes suggested. This principle is not unique to fluid dynamic lift; it is true of most phenomena of interest in physics. Dolphin (t) 09:56, 7 June 2023 (UTC)

I agree, my understanding is immature/rudimentary/inaccurate. This is not my area, I've just had to do some reading for related work and I found that the page added a lot of confusion early on in my study of the subject. I hope that someone with the expertise can edit the page to more accurately and clearly describe the process.

FropFrop (talk) 06:52, 8 June 2023 (UTC)