[ignayars]

Hi all!
I'm simulate unsteady flow in Fluent and I need write to file pressure force and viscous force on a wall every time step. I'm using UDF in parallel, but my UDF working wrong. After first time step Fluent crashes
UDf code :
DEFINE_EXECUTE_AT_END(compute_forces)
{

/* Initialiazation */
FILE *out;
real ftx, fpx, fvx;

#if !RP_HOST

Domain * domain;
Thread * thread;
face_t f;
real NV_VEC(A);
real Force_viscous_tot[ND_ND], Force_pressure_tot[ND_ND], Force_tot[ND_ND];
real Force[ND_ND], Force_viscous[ND_ND], Force_pressure[ND_ND];

domain = Get_Domain(1);
thread = Lookup_Thread(domain,9);//wall is 9
N3V_S(Force_viscous_tot,=,0.0);
N3V_S(Force_pressure_tot,=,0.0);
N3V_S(Force_tot,=,0.0);
N3V_S(Force,=,0.0);

#endif //!RP_HOST

#if !RP_HOST

begin_f_loop_int(f,thread)
{

F_AREA(A,f,thread);

/* Get wall shear force and pressure force on face */
N3V_VS(Force_viscous,=,F_STORAGE_R_N3V(f,thread,SV _WALL_SHEAR),*,-1.0);
N3V_VS(Force_pressure, =, A, *, F_P(f,thread));

/* Add forces */
N3V_VV(Force, =, Force_viscous, +, Force_pressure);

/* Accumulate viscous/pressure forces */
N3V_V(Force_viscous_tot, +=, Force_viscous);
N3V_V(Force_pressure_tot, +=, Force_pressure);
N3V_V(Force_tot, +=, Force);

}
end_f_loop_int(f,thread);
ftx = Force_tot[0];
fpx = Force_pressure_tot[0];
fvx = Force_viscous_tot[0];

#endif //!RP_HOST

#if RP_NODE

ftx = PRF_GRSUM1(ftx);
fpx = PRF_GRSUM1(fpx);
fvx = PRF_GRSUM1(fvx);

#endif //RP_NODE

node_to_host_real_3(ftx, fpx, fvx);

#if !RP_NODE

out = fopen("data.txt","a");
fprintf(out,"%13.5e\t%13.5e\t%13.5e\t%13.5e\n",CUR RENT_TIME,fpx,fvx,ftx);
fclose(out);

#endif //!RP_NODE[/INDENT]}


Thank you!

[kuldip]

Originally Posted by ignayars

Hi all!
I'm simulate unsteady flow in Fluent and I need write to file pressure force and viscous force on a wall every time step. I'm using UDF in parallel, but my UDF working wrong. After first time step Fluent crashes
UDf code :
DEFINE_EXECUTE_AT_END(compute_forces)
{

/* Initialiazation */
FILE *out;
real ftx, fpx, fvx;

#if !RP_HOST

Domain * domain;
Thread * thread;
face_t f;
real NV_VEC(A);
real Force_viscous_tot[ND_ND], Force_pressure_tot[ND_ND], Force_tot[ND_ND];
real Force[ND_ND], Force_viscous[ND_ND], Force_pressure[ND_ND];

domain = Get_Domain(1);
thread = Lookup_Thread(domain,9);//wall is 9
N3V_S(Force_viscous_tot,=,0.0);
N3V_S(Force_pressure_tot,=,0.0);
N3V_S(Force_tot,=,0.0);
N3V_S(Force,=,0.0);

#endif //!RP_HOST

#if !RP_HOST

begin_f_loop_int(f,thread)
{

F_AREA(A,f,thread);

/* Get wall shear force and pressure force on face */
N3V_VS(Force_viscous,=,F_STORAGE_R_N3V(f,thread,SV _WALL_SHEAR),*,-1.0);
N3V_VS(Force_pressure, =, A, *, F_P(f,thread));

/* Add forces */
N3V_VV(Force, =, Force_viscous, +, Force_pressure);

/* Accumulate viscous/pressure forces */
N3V_V(Force_viscous_tot, +=, Force_viscous);
N3V_V(Force_pressure_tot, +=, Force_pressure);
N3V_V(Force_tot, +=, Force);

}
end_f_loop_int(f,thread);
ftx = Force_tot[0];
fpx = Force_pressure_tot[0];
fvx = Force_viscous_tot[0];

#endif //!RP_HOST

#if RP_NODE

ftx = PRF_GRSUM1(ftx);
fpx = PRF_GRSUM1(fpx);
fvx = PRF_GRSUM1(fvx);

#endif //RP_NODE

node_to_host_real_3(ftx, fpx, fvx);

#if !RP_NODE

out = fopen("data.txt","a");
fprintf(out,"%13.5e\t%13.5e\t%13.5e\t%13.5e\n",CUR RENT_TIME,fpx,fvx,ftx);
fclose(out);

#endif //!RP_NODE[/INDENT]}


Thank you!

Hi ignayars,

Please define macro for unsteady simulation before #if !RP_HOST.

You have to define
real current_time;
current_time = CURRENT_TIME;


It may work.