WHAT IS DRAG? | SLIP STREAM EXPLAINED

[@adi_akash97]

loved the way of explanation.............with this video I got more clarity about fluid and drag........

[@jaswanths1193]

you guys explained very well. I totally loved it. Thank you

[@sanjayck8195]

very clear and good example. Thank you soo much and keep doing more such videos on complex fluid mechanics topics. ESCN

[@shadowgarden_47]

This video was very useful I have learn something new today thanks to you guys.thank you

[@ridwansyed5676]

you guys should continue making videos

[@SciencewithSteph]

I like this video! I work in renewable energy and modelling airfoils in different flow types (especially in wakes) is a very important part of my job! Your visualisations are very nice!

[@2BrokeScientists]

Thank you

[@birajmalakar7349]

What is the software you have used here 4:33?

[@pradeepojha5784]

awesome

[@hassaanidrees4622]

Informative Video. Thank You Can you explain that can a double-slit cylinder (initially a bluff body) helpful in reducing drag?

[@kishorlimje169]

Thanks

[@shriramkrishna6122]

Shouldn't the downstream pressure be lower? i.e P1 > P2. Didn't get the part where you say the particles have to work against an increasing pressure gradient. Great channel btw : )

[@2BrokeScientists]

Thanks Shriram. Great question. The pressure downstream is lower because particles would have had to follow the contour of the body to get back to the original pressure in the freestream which means they have to move into an adverse pressure gradient. But since they do not have enough energy to do that they "cheat" and separate from the surface of the body without increase in pressure l

[@rameshtumuluru9855]

what about drag flick in hockey ? is it related?

[@nowyouknow-sortof]

In the CFD simulation, the vortices were oscillating up and down, why does that happen?

[@2BrokeScientists]

Interesting observation. The oscillations you see is called vortex shedding. This phenomenon depends on the Reynolds Number(Re), at low Re when separation occurs behind a bluff body it is stable and you do not observe an oscillating motion and can be considered as stable. But when Re increases the instability develops which causes organised unsteady shedding(Wakes) which you observe. Interesting fact, the Tacoma narrows bridge collapse was due to this same phenomenon. When the frequency of shedding matches that of the object resonance occurs. This lead to large oscillations which ultimately lead to its collapse. Check out this video: kzbin.info/www/bejne/aZ7GnaNvhtJ2fdU

[@pavanramayanam4751]

What about drag at low velocities with no wake formed What kind of drag is predominant ? Pressure / shear drag or both?

[@2BrokeScientists]

Great question! At low speeds, the flow actually is susceptible to separation (called laminar separation) then you will have pressure drag. But in a situation where the flow is fully attached then the drag is completely skin friction drag

[@pavanramayanam4751]

@@2BrokeScientists at very low velocities (creeping flow)???

[@2BrokeScientists]

You’re right. Creeping flow is a Reynold’s number less than 1 and the flow is fully attached. In those cases the drag is completely skin friction

[@crisistg7315]

Drag is the reason that other sperm lost in the race