[teymourj]

Hi all,

A quick post-processing question: when user uses "wallGradU" utility in OpenFOAM the output is a matrix with three components. The question is whether the first, and therefore other components, are defined as:

1) wallGradU_x = dU_x/dy

OR

2) wallGradU_x = dU/dx ?

I believe that definition number 1 is the correct one. Meaning:

(wallGradU_x, wallGradU_y, wallGradU_z) = (dU_x/dy, dU_y/dy, dU_z/dy)

However, needed a confirmation.

[mugabe2204]

Hey Teymour,

Though its quite an old post. I was working on something similar.

Considering this

forAll(wallGradU.boundaryField(), patchi)
{
wallGradU.boundaryField()[patchi] =
-U.boundaryField()[patchi].snGrad();
}


Source : https://github.com/OpenFOAM/OpenFOAM...dU/wallGradU.C

I would think the same you have mentioned. That the three components being dux/dn, duy/dn, duz/dn with n being the normal to the surface.

Cheers