Hi all! I`d like to use UDF for FLUID with Source-Therm definition to simulate a Porous-wall. I´d like to define zero velocity in certain cells, and a free stream for the rest of the cells. How can I define the "source" and the "ds[eqn]" in the Define_Source makro? Have you an idea?

Thanks! Timi

you don't need to use a Define_source UDF for this problem. velocity values can be fixed using the "Fixed Values" panel in the fluid boundary conidtions.

Thank you! But how can I define Fixed Values with UDF? Which makro can I use?

Timi

I think you can use the DEFINE_PROFILE macro but i'm not certain

I have done with DEFINE_PROFILE, and I have always got, that the y-coordinates are 0.00015m, when the y range is 0-0.002m. Do you know why? That´s the programm-text:

DEFINE_PROFILE(fix_vx_value, t, i)

{

#define r 0.00025

cell_t c;

real x[ND_ND];

real y;

begin_c_loop(c,t)

{

C_CENTROID(x,c,t);

y=x[1];

printf(" y: %12.6f ", y, c);

if (fabs(y-0.001) > r)

{

printf(" y: %12.6f ", y, c);

F_PROFILE(c,t,i)=0;

}

}

end_c_loop(c,t)

}

Thanks! Timi