[krishnaA]

can anyone brief me, whether newton's law of viscosity works in laminar sub layers zone of Turbulent Boundary Layer ? if it is so why we are going to wall function in that layer.

[FMDenaro]

Originally Posted by krishnaA

can anyone brief me, whether newton's law of viscosity works in laminar sub layers zone of Turbulent Boundary Layer ? if it is so why we are going to wall function in that layer.

the law is valid everywhere in the fluid and the wall function are used when you do not have a enough grid resolution to describe the boundary layer:


http://www.cfd-online.com/Wiki/Wall_functions

[krishnaA]

Originally Posted by FMDenaro

the law is valid everywhere in the fluid and the wall function are used when you do not have a enough grid resolution to describe the boundary layer:


http://www.cfd-online.com/Wiki/Wall_functions

Thank you for your replay, is it right idea to calculate the shear stress in laminar sub layers using liner relationship of newton law of viscosity, and compare for the results what i get from CFD.

My 2nd query is, if i have enough grid resolution near wall (keep the high accept ratio in maid) what make the sense to calculate wall shear stress using the wall function and acting it to the source term in momentum equation with out solve them directly.

[FMDenaro]

I suggest to study the topics in this book

https://www.scribd.com/doc/50191605/...ing-CFD-Wilcox