Fluid Mechanics 101 : Why does fluid flow follow a contour?

Have you ever wondered why a fluid flow tends to follow the shape of an object in the flow? In this video, we try and explain how fluids should be modeled as a continuum and how that affects their behavior.
Acknowledgments- Thanks to Sanjeet Desai for the videography and Ankith John for the editing suggestions. Thanks to Athreya BJ for the creative inputs.
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[@vishalm9160]

At 2:14, you were saying about the pressure the particles above exerts on the fluid near the surface, how does this make it follow the surface. Is this due to a low pressure region created below this set of molecules which gets deflected during the initial stages of the flow, and the above fluid molecules just turn the flow into this due to the pressure gradient...???

[@kalpanapatil4864]

Answer to your question is , that's not because there is something there to stop it or bounce back but because there is no pressure gradient that will cause fluid to flow in that direction. Fluid flows at right angles to the equipotential lines that flow down a slope, would flow at right angles to the contour lines.

[@2BrokeScientists]

You are spot on! In classical mechanics, there is no continuum, meaning no pressure gradients, but in fluid flow, the presence of pressure gradient causes the flow to deflect. For the flow around the cylinder, we have used potential theory, so the streamlines you see are indeed perpendicular to the equipotential lines. Thanks for your input! We will also explain potential flow in more detail in our next video.

[@abhinandpusuluri8865]

Great video boys! Application for a special appearance :P

[@2BrokeScientists]

Thanks Abhinand! We will keep you posted on the next videos

[@sksamsulhuda6726]

continuum hypothesis can lead to inaccurate results in applications like supersonic speed flows, or molecular flows on nano scale.

[@2BrokeScientists]

You are right! There is also a quantitative value to represent whether a flow can be modelled as a continuum or not, which we will deal with in the next video.

[@santhoshn3636]

Kushal , kindly include Knudsen Number to model fluid as a continuum, Fluid as a continuum means, we consider fluid as continuous medium despite being fact that at molecular level it is not continuous. we use this assumption so that we can make use of well known differential calculus to solve the physical problems.

[@rohitbhosle6521]

Superb video 😍

[@mailrmpmailrmp]

Friends, Interesting topic. Good luck to your channel.

[@2BrokeScientists]

Thank you Sir!

[@prayashpanda7884]

Why should high pressure of farfield and low pressure near airfoil cause fluid to deflect around the airfoil?

[@2BrokeScientists]

Good Question! The pressure gradient is what gives rise to the centripetal force which causes the fluid particles to turn.

[@poonammishra8544]

Here making the assumption of fluid as a continuum is independent of compressibility i.e.fluid flow is taking such shape because of the continuum assumption and not for reasons like compressibility .Is it correct ?

[@2BrokeScientists]

Yes, In this case we are specifically talking about continuum. But you make a very nice observation, In super sonic flows the flow velocity and the information at which information propagates in the fluid are of the same order. Because of which the flow will not be able to adjust to a sudden change and Hence we observe shocks.
Do watch our videos on shock waves to get some more info

[@shanthmurthymg8605]

Good job guys. Great video. You can take daily application of fluid mechanics and explain in simple words.

[@2BrokeScientists]

Thanks Shanthmurthy!

[@rameshkgowda1576]

This is good attempt by you people. I have shared this to my PG students. All best to you both . Kushal you doing appreciable wirk

[@vijaykumark194]

Very nicely presented. 👌👌👍

[@2BrokeScientists]

Thank you!

[@raghavbhat9004]

Excellent. All the best👍👍

[@2BrokeScientists]

Thank you!

[@dr.rajendrakumarharsoor1239]

Excellent presentation

[@2BrokeScientists]

Thank you sir!