[mpapon]

Hello,

I am working on a simple problem where my working domain is a rectangular 2D plate. Inlet and outlet are on left and right side respectively and top and bottom are the two walls. I want to set the bottom wall as moving wall and it would move at a velocity of 0.5 m/s in +ve X direction for 10 seconds and then it moves in opposite direction (-ve X direction) with the same 0.5 m/s in next 10 seconds.
I am new in UDF. I could find and modify one UDF for +ve X direction but I can't write one for -ve one.

Here it is:

# include "udf.h"

DEFINE_PROFILE(moving_plate, thread, equation)
{
float x[3],y;
face_t f;

begin_f_loop(f, thread)
{
F_PROFILE(f,thread,equation)= 0.5;
}
end_f_loop(f,thread)
}

For -ve X direction, I tried the same code changing as this
F_PROFILE(f,thread,equation)=- 0.5;
But, it doesn't work.

If it did work I would then go for creating a loop with if/else statement combining the whole.
Can anybody please help?
Thanks.

[FMDenaro]

I am not sure but you can check if you need to prescribe only the magnitude and the key to get working is to prescribe the unit vector given the direction..