It's because the order of magnitude of turbulence fluctuations are assumed to the similar in all directions. I.e. that the fluctuation in the wall normal direction v is similar to the fluctuation in the streetwise direction u. It's true this won't be the case very close to the wall but as you move further away this is okay.
@@yusufsenol6992 yes true! but remember that here the order of magnitude analysis is intended only as a way to see how the equation behaves, its only meant to give approximate balance of terms.
Thank you, I understand it now thanks to your explanation🙌
why in 2D continuity, you moved the 1st term of the equation from left side to the right side, the sign did not switch?
Why is (uv)overbar converted to (uu)prime in the last term of the 2d momentum equation
It's because the order of magnitude of turbulence fluctuations are assumed to the similar in all directions. I.e. that the fluctuation in the wall normal direction v is similar to the fluctuation in the streetwise direction u. It's true this won't be the case very close to the wall but as you move further away this is okay.
Alistair Revell I got it now. So many assumptions is there in turbulence, isn’t it?
@@yusufsenol6992 yes true! but remember that here the order of magnitude analysis is intended only as a way to see how the equation behaves, its only meant to give approximate balance of terms.
Alistair Revell Outstanding video series by the way. Thank you.
@@yusufsenol6992 thank you very much