Constant Pressure Boundary Condition Not Holding!!
 

Hello,

I am running a simulation where I have a 6cmx20 cm rectanglular tank that is filled with water. I want to apply a pressure of 400000 Pa to the bottom of the tank and take a look at the resulting velocity fields.

I made a UDF to put the pressure condition at the bottom of the tank.
However for some reason, the pressure is only holding for the first time step and then gradually decreasing to zero.
I would like the pressure pulse to stay at 400000 Pa at the bottom of the tank for the entire simulation.
I appreciate your help and time. The UDF is below.

#include "udf.h"
DEFINE_PROFILE (unsteady_pressure, thread, position)
{

face_t f;
real t= CURRENT_TIME;

begin_f_loop (f,thread)
{
F_PROFILE (f, thread, position )=400000;
}
end_f_loop (f,thread)

}