[MUMMED]

Hi,
I am trying to find every 9 component of a stress tensor on a wall, I read the forum but I didn't get much,all I have ,is Wall Shear X,Y and Z in CFD-post.
Am i missing something or those component are principal ones?

[Opaque]

A review of the vocabulary will help:

Normal = Normal unit vector to surface of interest

sigma = stress tensor at a point (9 components, 6 different ones since it should be symmetric for non-polar fluids)

T = stress vector on a point in the surface of interest
= T_normal + T_tangential (3 components)

How are they related ?

T = sigma . Normal (this is a tensor multiplying a vector)

T_normal = T . Normal

T_tangential = T - ( T . Normal )

T_tangential is the Wall Shear vector.

Hope the above helps,

[MUMMED]

Originally Posted by Opaque

A review of the vocabulary will help:

Normal = Normal unit vector to surface of interest

sigma = stress tensor at a point (9 components, 6 different ones since it should be symmetric for non-polar fluids)

T = stress vector on a point in the surface of interest
= T_normal + T_tangential (3 components)

How are they related ?

T = sigma . Normal (this is a tensor multiplying a vector)

T_normal = T . Normal

T_tangential = T - ( T . Normal )

T_tangential is the Wall Shear vector.

Hope the above helps,

I really appreciate your reply,and that was helpful,then what does Wall Shear X,Y and Z exactly mean? sorry if it's stupid question

[Opaque]

T = stress vector = force vector per unit area

T_tangential = tangential force vector per unit area
= Wall Shear Vector

[MUMMED]

Originally Posted by Opaque

T = stress vector = force vector per unit area

T_tangential = tangential force vector per unit area
= Wall Shear Vector

Thanks again
I think I ask my question badly,
my real question is how can I find T_xy or other component, in CFD-post i just got Wall Shear X,Y and Z