compressible flow - WATER !!
 

Hi mates, I´m dealing with single phase problem. The fluid is liquid. There´re two pressure inlets. One is a constant value and the other is time-dependent sinusoidal pressure declared in UDF. Because of fast unsteadiness the water density is pressure-dependent (also UDF)The UDF is shown below:

/************************************************** ***************** periodic boundary condition - pressure, density ************************************************** ******************/

#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)=100e+05+900e+05*sin(1 0000*3.141592654*t);

} end_f_loop(f,thread) } DEFINE_PROPERTY(cell_density,cell,thread) { real ro; real p = C_P(cell,thread);

ro = 998/(1.0-(p-101325)/2.2e+09); return ro; }

I´m using segregated solver. If using just time-dependent pressure, it is O.K. If using also pressure-dependent density,it is immediately diverging.

Could you look up any problem?

Thanks in advance!! Jan

Hi Jan,

Have you fixed the problem above?I also have very similar truble with you. the compressible liquids or air are hard be computed.

thanks
zhaohui