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compressible flow - WATER !!

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Old   October 22, 2007, 04:00
Default compressible flow - WATER !!
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Bohis
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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

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Old   May 24, 2011, 19:26
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ZHAOHUI
Join Date: Jan 2011
Location: QLD
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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
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