Flow Separation - Boundary layer separation explained

[@pedrolopez-velarde2305]

Kudos for your short and clear explanations, thank you

[@AirShaper]

You're very welcome!

[@chaewoonsong3525]

Superb explanation and diagrams - thanks a lot!

[@snehamaity2314]

Thank you for explaining in great detail 😊😊

[@smferreiro2610]

Excellent explanation! (The video, though, featured very low volume, sometimes hard to listen to without headphones in a noisy environment)

[@AirShaper]

Thank you very much Santiago!! Yes, we will fix the volume for the next recording :) Thanks for letting me know!

[@denizcakar8285]

In the 2:05, you mentioned that " If the pressure gradient in the horizontal plane is positive or zero, velocity gradient in vertical is positive." but it looks in the image and from the knowledge it must be negative pressure gradient right?

[@TheShavarin]

@@denizcakar8285 I was thinking too the same and then came here to check if some one has commented.

[@ahmedwael.729]

I like your explanation. Thanks man

[@AirShaper]

You're very welcome!

[@varunak1683]

Amazing explanation. Could be a little louder !

[@AirShaper]

Agree, we've turned up the volume on more recent videos

[@fajaranggara9117]

nice video, I just want to ask on flow over plate, what is the meaning dp/dx=0??,. if dp/dx=0, then in flow over plate, separation will not occur even we extend the length of plate ??

[@AirShaper]

Dear Fajar, dP/dX = 0 relates to the overall flow, where the velocity is constant. Because of the bernoulli equation, this means the pressure is also constant. However, you are right, this is a simple approximation. Because of friction (which indeed increases as the length of the plate increases) the pressure can indeed vary as you travel along the plate. And, as the boundary layer grows thicker, you can have a transition from laminar to turbulent at a certain point. This video is also quite interesting kzbin.info/www/bejne/a6uvdKKcebinlbM

[@SafiHalim]

Thank you very much! Very good explanation!

[@AirShaper]

Thank you!!

[@tangus7335]

why does the flow start to slow down at the midpoint, I assumed due to friction but my proffessor told me the flow doesn't start slowing down at the midpoint. Can anyone clarify

[@asdfasdfafsadf7883]

Mistake: If the pressure gradient is NEGATIVE or zero, then the velocity gradient in the vertical direction is a positive one.

[@berkekus7053]

Great video!

[@AirShaper]

Thanks!

[@josue8632]

why does the curvature influences on the pressure gradient in streamwise direction?

[@AirShaper]

Dear Josué, I don't think I fully understand the question - if by streamwise direction you mean the flow lines, the pressure changes as the air slows down & speeds up (linked to the Bernoulli effect). What do you mean with the streamwise direction?

[@raphikk]

Very clear video

[@AirShaper]

Thank you very much Raphael!

[@livinginthisgalaxy7961]

Would it be sensible to make surfaces more complex with sensors like shark skin that can adapt to the given positive or negative flow?

[@AirShaper]

There is definitely a growing interest for "shape morphing" objects that can change shape in function of the aerodynamic goals. Or flexible materials, that deform under aerodynamic loads.

[@bagmitabaishnabi3979]

Best explanation

[@abdelrahman4436]

brief and informative . great video

[@AirShaper]

Thanks!!

[@jorbedo]

Can you try to keep the audio levels the same for all your videos?, some are too high, some too low. Thanks.

[@AirShaper]

Very true - we had this comment before and we switched to a new mic for newer videos. Should be better for more recent ones!

[@David_Mash]

What would be the best shape if I want to maximize friction

[@AirShaper]

Hi David, we haven't had that question before :) Surface friction goes up with velocity, viscosity, surface area, surface roughness ... so those would be the parameters to work on. Keep in mind that you may trigger separation, creating a turbulent flow which has different friction properties as well.

[@David_Mash]

@AirShaper I am working on a tesla turbine boundary layer turbine but with a cone or bowl shape to maximize friction instead of multiple discs.

[@AirShaper]

@@David_Mash Then indeed the surface roughness is an important parameter :)

[@manjunaths5002]

Hi. Your videos are really good and easy to understand. Can you make a video on how to start a career in aerodynamics/CFD?

[@AirShaper]

Hi Manju, thank you! We have a blog exactly on that topic: airshaper.com/blog/building-your-career-in-aerodynamics Good luck!

[@manjunaths5002]

@@AirShaper thank you.

[@HahaHub1986]

Good! Exp..... But i want ur qualification and affiliation

[@AirShaper]

You mean my educational background, company, ...?

[@HahaHub1986]

@@AirShaper yes! PhD Msc ... and working company. university or other

[@AirShaper]

@@HahaHub1986 I don't feel I owe the community this information - the content needs to be good and speak for itself. Nevertheless: Education - Masters in mechanical engineering (with just the basics of fluid mechanics) - Post-grad degree in product design - Degree in car mechanics (4 years of after-work evening schooling) - Self-study on deeper CFD principles Experience - 10 years of experience in OpenFOAM (CFD environment) - 7 years as project manager for FEA/CFD simulations & wind tunnel testing at engineering agency (prior to founding AirShaper) - 8 years of experience prototyping & developing the online simulation platform AirShaper (I'm the founder / CEO) - Patented aerodynamics concept (see airshaper.com/cases/aquilo-patented-aerodynamic-concept-car) - Occasional teaching on aerodynamics at universities / private companies - ...

[@annasolzh]

Why is the volume so low??

[@AirShaper]

Fixed it for future videos!

[@bunnyonabunwithagunnicepun5689]

That is quite a lot of Mathematics... I'm more of a real-world trial-and-error kind of guy, but this was still incredibly useful, nonetheless!

[@AirShaper]

It's indeed fairly theoretical, but perhaps you can experiment in real life with some tufts on a car? We had fun doing so on this VW Beetle: airshaper.com/videos/diy-aerodynamics-2-vortex-generators/MC6woj6tsQY

[@Mohamed_zyd]

low voice

[@AirShaper]

That's true - we corrected this for more recent videos, thanks!

[@vtwl24]

sound volume problem

[@AirShaper]

True - we corrected this on more recent videos

[@hmabboud]

I cant hear anything

[@mcthunderstick2374]

Should get that checked by a doctor

[@hmabboud]

@@mcthunderstick2374 I went. He told me to get back to you. Do you know what did he say? You need to get check-in in a mental clinic.

[@gamukamamichael9956]

Yo volume is low speak louder please

[@AirShaper]

Fully agree - we bought a new microphone and increased the volume for later videos!

[@deepaksivakumar651]

Are u hiring interns?

[@AirShaper]

Not at the moment, we'll post it on airshaper.com/jobs when we do. Best of luck Deepak.

[@deepaksivakumar651]

@@AirShaper can't wait :)