[aladdincham]

Why Stress-strain rate is equal to Vorticity in Boundary Layer?
Hi friends,
Recently, I read some paper that said Stress-strain rate S is equal to Vorticity in Boundary Layer, Who can give me some expression about this.
Thx.

[FMDenaro]

Originally Posted by aladdincham

Why Stress-strain rate is equal to Vorticity in Boundary Layer?
Hi friends,
Recently, I read some paper that said Stress-strain rate S is equal to Vorticity in Boundary Layer, Who can give me some expression about this.
Thx.

that is quite correct... consider a 2D flow over a flat plate, vorticity is z = du/dy - dv/dx, the stress at the wall is:

tau_wall = mu*du/dy|w = mu*(z + dv/dx)|w.

For a not permeable wall v=0 and tau_wall = mu*(z)|w