traction free bc
 

Hi everyone

Does anybody know haw can I introduce "traction free" BC at the outlet of my domain in CFX?

Regards

What is a traction free BC?

this relation is called "traction"

T=-pI+2*mu*D,D=0.5*[grad(u)+grad(u)^T]

whenever it equals to zero, there is no traction or we can say it is traction free

by the way "mu" is viscosity of the fluid

I assume u is the velocity field. What is p and I?

Can you explain what is the physical significance of this?

P is pressure and I is the Identical matrix. it is said that this kind of bc does not affect the upstream flow conditions significantly

I see.

You may be able to do it as a CEL function on an outlet boundary condition with a CEL specified velocity or pressure, but you probably have to implement it in fortran.