[arash.mp]

Hi everyone,
i have a 2 layer pipe (2D axisymetric) which the outer layer is a porous medium and a fluid flows through the core of the pipe. ( i attached the geometry below).
the fluid permeates through the porous medium due to the pressure difference ( as i shown in the geometry there are 2 pressure outlet B.Cs that force the fluid to permeates through the porous wall).
i want to calculate the SHEAR STRESS on the interior B.C (shown in the figure) with the relation viscosity*shear_rate.
i can do it with CUSTOM FIELD FUNCTIONS, BUT for some reason (calculating variable properties etc, ) i have to write a UDF for this purpose!
for summary, i have to CALCULATE shear rate along an interior B.C, multiplying the shear rate to viscosity and STORE the values and PLOT it with usage of User defined memory(UDM).
Can anyone help me with writing the UDF?
at the end i want to change the geometry to 3D in future!if the should be a change for that please tell me,
thank u.

[hitzhwan]

Originally Posted by arash.mp

Hi everyone,
i have a 2 layer pipe (2D axisymetric) which the outer layer is a porous medium and a fluid flows through the core of the pipe. ( i attached the geometry below).
the fluid permeates through the porous medium due to the pressure difference ( as i shown in the geometry there are 2 pressure outlet B.Cs that force the fluid to permeates through the porous wall).
i want to calculate the SHEAR STRESS on the interior B.C (shown in the figure) with the relation viscosity*shear_rate.
i can do it with CUSTOM FIELD FUNCTIONS, BUT for some reason (calculating variable properties etc, ) i have to write a UDF for this purpose!
for summary, i have to CALCULATE shear rate along an interior B.C, multiplying the shear rate to viscosity and STORE the values and PLOT it with usage of User defined memory(UDM).
Can anyone help me with writing the UDF?
at the end i want to change the geometry to 3D in future!if the should be a change for that please tell me,
thank u.

Hi,do you deal with your problem?

[arash.mp]

Originally Posted by hitzhwan

Hi,do you deal with your problem?

Hi, not yet! do you have any solution?

[vinerm]

You can use velocity gradients to define the shear stress at any location in a UDF. Velocity gradients can be accessed using _G or _RG, e.g., C_U_G(c,t)[0] implies x-component of gradient of x-velocity.