Everything is really well presented. However, we should be careful in stating that Turbulence reduces drag. Turbulence does not reduce drag. On a given surface area/length laminar flow always has less drag than turbulent flow. This sort of friction is called skin friction. The friction that happens when a flow wets the surface flowing. However for blunt bodies like a sphere, the flow separates at the equator causing "dead water" effect at the back of the back. When a flow separates, this creates a higher drag than laminar or turbulent flow, known as the pressure drag (form drag). This form drag is very high and most of the time it's greater than skin friction. What dimples in the golf ball does is that it energizes the boundary layer and flow stays attached for a greater distance on the surface. This flow attachment reduces flow separation, hence reduces form drag which in turn reduces the overall drag. It needs mentioning that in a situation where a flow does not separate (airfoil at low angle of attack), turbulent flows will increase the drag compared to laminar flow.
Now I am clear with how Reynolds stress is related to turbulence modelling with your Expalnation...!!! looking forward for more lectures from you..Sir Thank you...:)
It's actually the opposite. When the velocity (i.e. the kinetic energy) increases to the point where the viscous effects can no longer "control" it, turbulence occurs.
Yes It is. Actually you can win Millennium Prize in Mathematics from CMI,Mass (USA) by solving it. And most probably Nobel Prize and a few other honers will add a few more millions to your kitty....... :-)
![[CFD] The k-omega Turbulence Model](http://i.ytimg.com/vi/26QaCK6wDp8/mqdefault.jpg)
Everything is really well presented. However, we should be careful in stating that Turbulence reduces drag. Turbulence does not reduce drag. On a given surface area/length laminar flow always has less drag than turbulent flow. This sort of friction is called skin friction. The friction that happens when a flow wets the surface flowing. However for blunt bodies like a sphere, the flow separates at the equator causing "dead water" effect at the back of the back. When a flow separates, this creates a higher drag than laminar or turbulent flow, known as the pressure drag (form drag). This form drag is very high and most of the time it's greater than skin friction. What dimples in the golf ball does is that it energizes the boundary layer and flow stays attached for a greater distance on the surface. This flow attachment reduces flow separation, hence reduces form drag which in turn reduces the overall drag. It needs mentioning that in a situation where a flow does not separate (airfoil at low angle of attack), turbulent flows will increase the drag compared to laminar flow.
Qayyum Mazumder Thank you..
So true....
Now I am clear with how Reynolds stress is related to turbulence modelling with your Expalnation...!!!
looking forward for more lectures from you..Sir
Thank you...:)
Turbulence explained in a laminar way .. thanks
I enjoyed all your lecture series. I am also fan of your accent. looking forward for more lectures from you.
Finest presentation. The pictorial explanation is really good.
Great explanation of difficult concept! Thanks buddy!
Damn this was super clear. Great examples/explanations.
Excellent intro to this certain theme.
Please make physical meaning of NS equations and divergence physical meaning video too. Thanks for such superb explaination.
Very good efforts. It will be better with improving your English accent :)
We know interia is a resisting force, how can it be responsible for accelerating an object and how can it increase the velocity?
Malayali aano?? Ascent seems to be so. 😊
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Nice sir very much thank you sir.....
Love the accent.
i guss terbulance happens because after some laminar flow fluid has less energy,it gets nervous gets out of control,turning into randomness
It's actually the opposite. When the velocity (i.e. the kinetic energy) increases to the point where the viscous effects can no longer "control" it, turbulence occurs.
is this a part of cfd ?
Yes It is. Actually you can win Millennium Prize in Mathematics from CMI,Mass (USA) by solving it.
And most probably Nobel Prize and a few other honers will add a few more millions to your kitty....... :-)
Thank you
I have heard the voice but i am not able to recognize the preson
effect of turbulence reduces drag ??? it is a wrong claim. just in special cases, turbulence can reduce wake regiıon hence drag
nice
Accent is too hard to me
boopity beep! beep! Beep! bopity !! durka durka stan
couldn't you find somebody else with a good English language????
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