13. Secondary Flow

[@jorgesilva5337]

Barry Belmont great videos! thank you for sharing. Where could I get video #12? That's the one on Boundary-Layer Control

[@EpiScintilate]

Thanks for the videos. Awesome demonstrations.

[@xingyuansheng]

Thank you for uploading this!

[@jinlaizhang312]

what's the experiment device in this video?

[@joaquinmura9382]

Thank you for sharing!

[@arjangalidai1]

Thanks a lot. It was really useful.

[@khalilalani2707]

interested video,thank you

[@LavanyaKumarB]

Thanks for the upload.......It's tooo gooood.

[@ivanhunter3907]

Good

[@nikan4now]

Can someone explain why the lecturer seems to assume that the pressure gradient is the same for the example cases where the velocity is once large and once small at 10:15s?

[@mamidia1]

+Nikan RT I think it's because he's considering the pressure gradient at the streamline, which will be constant alone the same streamline. but yeah I'm confused too since if r (radius) changes, the streamline should too, and hence pressure gradient should change. not very sure on this :/

[@EpiScintilate]

The main point is when you go towards the bottom the velocity reduces (due to the presence of the surface) and this means the radius must be lower. So at the bottom surface the fluid flows towards the centre. The mechanical analog is the circular motion of a mass on a string. If the velocity is reduced the radius reduces.

[@ASJC27]

I know this is an old comment, but for anyone still interested, the answer is that one of the fundamental characteristics of boundary layers is that the pressure gradient normal to the surface is almost exactly zero. This means that the pressure at all depths within the boundary layer is the same as the pressure at the point where the boundary layer ends. So in a case of the rotating vortex flow, fluid within the BL experiences the same pressure gradient towards the center as the fluid just outside of it, but since the flow is slower within the BL, the centrifugal force can't balance the pressure force and the BL fluid is pulled towards the center.

[@Amletagain]

10:38 reminds me orbital mechanics, is that the same concept ?

[@blam320]

No. Orbital mechanics and fluid mechanics share nothing in common.

[@roch5547]

Of course they do. Both start from Newton's Laws

[@mamatalu]

Thank you!! +1 for you

[@RabbitWolfpack1]

Anybody searching for the answer the mistake he made at 5:45? :P Don't look, it's not here.