[javad.gh]

Hello guys,
i am modeling following problem in fluent. i tried mass flow inlet but my simulation went wrong.
how can i solve this problem in transient calculation? i used this udf for free surface level. do i use pressure inlet?
thanks a lot ..

*********************************
#include "udf.h"
DEFINE_TRANSIENT_PROFILE(free_surface,CURRENT_TIME )
{
real f_surface=0.0 ;
real ti ;
ti = CURRENT_TIME;
if (ti < 1)
{
f_surface = 0.5 ;
}
else
{
f_surface = 5 ;
}
return f_surface;
}