Science experiment - Fluid Mechanics

[HY938DV]

Why we didnt see any downwash?

[DaylightDigital]

Bloodly brilliant vid! Lift requires viscosity!

[izu1989]

Very good stuff man!

[fquarn]

I would love to use this video in a Boy Scout Merit Badge class. Can anyone tell me if it is copyright protected?

[xDImGellinDx]

@fquarn You wouldnt get sued for using this if you are just showing it to your class.

[sovakuliana]

I think it's midnight sonata

[thedaveman55]

is this modeled by inviscid flow? doesn't seem to satisfy the Kutta condition at the trailing edge.

[raserrobi99]

Please send me the link of this software

[bbbcreations]

What is the name of this song?



[richarddale76]

surprised at that AOA it didnt stall

[allydea]

Man, so many misunderstandings and dogma-physics in the comments. :( but then again aerodynamics is a pretty difficult field.

[raycod84]

@allydea You think this is bad? Check out some of the "free energy" videos!

[DiNoZs1]

For the people having hard time understanding this...What you here see is a airfoil with high AOA . air above the airfoil goes fast but air under the wing goes slow. Fast air= less air pressure / slow air =more air pressure, which result in lift because air tries to equelyze , more air onder the airfoil lifts the airfoil to reach the low pressure ,getting the airfoil in it's way move upwards

[mabalint]

@DiNoZs1 Oh yes, this is exactly what uneducated physics teachers are saying in high schools... Far away from the truth ;)

[DiNoZs1]

@mabalint

Tell me the the truth then :)

[mabalint]

@DiNoZs1 I am glad to help you.. It is not true that air takes the same time to travel above and below an aircraft's wing.[215] This misconception is widespread among textbooks and non-technical reference books, and even appears in pilot training materials.

[mabalint]

There is also lift force, if the speed above and under the airfoil is exactly the same, see bats, hang gliding etc..

[MrQuuem]

Was this done by experiment or by simulation? Because I find several things odd about these results...

Firstly, the flow seems way to attached to the airfoil for such angle of attack. I would expect some recirculation by the end.

Secondly, Kuta condition is not followed . As a result, the rotational is zero, and there is no lift generation. (that would be ok, if you maneged to film a starting vortex)

[adas1023]

just seeing the words "fluid mechanics" is making me weep, that exam was a traumatising time in my life... at least its all over.

[IQ20000Berta]

scary about the count number, maybe an airplane will crash soon

[lucabadue]

10 guys prefer helicopters

[Dr904]

@lucabadue helicopter wings uses the same technology.

[tradward]

wrong

[superhornet59]

This doesn't strike me as accurate. Most 'simple' airfoils without the help of any kind of vortex generating device stall out at about 15 degrees alpha. This is significantly more then that, and yet still mostly (except the trailing edge there) pretty laminar. What's the point of this kind of 'wind tunnel' if it's inaccurate anyway?

[Pono421]

what is the name of the pice you where playing in your vid? i love that song.

[trollgoal]

@Pono421 ...Beethoven, Moonlight Sonata

[AROminor]

Kutta condition VIOLATED

[piblo87]

@AROminor

I don't think the Kutta condition applies in this case, it applies only in potential flows where friction is not considered. The stagnation point at the trailing edge is caused by friction.

[SidewaysGts]

@TheTelevisedRevo Dont know if I agree. Auditory beauty goes along nicely with the beauty of nature for me.

[MrQuuem]

Why Kutta condition is not being obeyed?

[DanFrederiksen]

weird how lines climb so high and get over the surface. looks like they should pass under

[YellowCakeKid]

@DanFrederiksen yup, just shows how early the pressure starts to drop on the top side

[niinja2]

@DanFrederiksen

they climb because there is air below them (only its not colored) and air pressure is reducing above them

[aboriani]

@DanFrederiksen those lines that climb get "sucked" to the upper section because there is a low pressure zone, caused by a acceleration of the upper section fluid.

[Burstigull]

It's Beethoven, don't know why anyone would dislike that tbh.

[Azurlake]

@Burstigull Maybe because it's been dramatically shrinked and it loss all of the spirit.

[Dragonsintuxcedos]

@Burstigull What's the name of that song?

[KarpatycGhost]

@Burstigull simple they were deaf and brainless .... (@_@)

[Flygify]

Hi!

I like this clip and I wonder if i can show it in the new Science center at the Swedish airforcemuseum where I work?

/Kristina

[sharethispoison7]

OK, on behalf of all youtube users that work in retail or the service industry.... you're an asshole. Yet another corner we must all turn, only to find, this fucking song. Get this song out of my science!

[rambopussycat]

where is mute, aaaaa there it is:)

btw nice vid.

[COD5252]

off topic

[mindhaze]

music?

[iMakeMoneyOnlinee]

How fast would this normally be?

[gaaraxdancing]

...awesome.

[hateisjustaword]

wtf

[2mil8]

Which is the fluid that use used?

[criticalmass181]

O.K....it's a stalled wing. Are you making a connection between the song, and a stalled relationship, or are you just wasting everuones time?

[dnealio]

Not very stalled though. Those suction side streamlines looked pretty much attached to me!

[criticalmass181]

You've got a point....My mistake. I was looking at the directional flow, and assuming. The angle of attack looks too great to sustain lift, but that's just an opinion. In any case, the chord looks too symetrical, and it's a CGI, so it's of little consequence to real aerodynamics, I guess. Take care.

[gaaraxdancing]

@criticalmass181

At spell correctly when you're criticizing someone.

[Blightmouth]

why bother?

[gaaraxdancing]

@Blightmouth

good point.

[Blightmouth]

@gaaraxdancing

:D

[ryanair1313]

its called the first words witch his sings.

[socal2121]

"hella gay" by The Fags

[Ithinkmynameiseva]

hey there delilah-plain white T`s

[Peacekeeper118]

Its a guitar :P

[Timuouo]

what happened to Kutta-Joukowski condition??

[kikkarose]

@Timuouo Kutta it's just a semplification of the problem: no boundary layer. so airfoil is only a streamline under this assumption.

sorry for my english ; )

[Timuouo]

@kikkarose Kutta is used when we represent the wing as a sink and a source, in which case it is a set of streamlines like u said. However, Kutta is not a simplification, but instead an improvement. Remember, without Kutta we would have a singularity at the trailing edge. It is also used in viscous flow, where we do get a boundary layer... in fact vscous flow is one of the reasons why we need Kutta condition

[Timuouo]

@kikkarose and in this demonstration we don't really see the Kutta condition.. its not difficult to include a Kutta condition in a 2d code, and would give a much more useful result, because you would be able yo calculate lift/drag etc (which i dont think u could in this case)

[sneakytouchyourplace]

there exist any software that can perform simulation like this?

[medinmedin]

fluent

[sapingil]

The ANgle of attack should not be more than 16 degrees am i right? the average should be 13-14 to avoid turbulence

[Yassoua]

You cant avoid turbulence unless ur flow is laminar. You were probably refering to "stall"

[sapingil]

really? thanks for the info im just a freshmen in AMT course atleast i learned something from you. Thanks bro

[keeevan]

different wings will stall at different angle of attacks, but generally 16 is about stall when in straight and level flight

[looncraz]

A faster speed should be used to illustrate the results as they would be expected ( rather than just lines flowing gently around a shaped and angled foil ).

[laposte07]

thank u

[ermarcio]

not correct: the flow follows the trailing edge whitout sharp angles!

[spychopath]

Doesn't look like a simulation. Looks like a Hele-Shaw cell to me.

[spychopath]

No, I'm wrong, it is a simulation!

[sidthegr8est]

looking at your comments was a funny experience ...

[bertazoid]

What did you use to simulate this?