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September 24, 2014, 16:39 |
Ploting Drag Force Vectors
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#1 |
Member
Camilo Costa
Join Date: Jun 2009
Posts: 34
Rep Power: 17 |
Dears Members,
Anyone has some experience for write an udf to plot the vectors of drag force in a multiphase flow modeled by Euler-Euler approach with VOF model enable? More specified, I want to see the vectors of the drag force near the interface liquid-gas, responsible for create slug flow pattern in two phase flow. Thanks!! |
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September 26, 2014, 14:36 |
Find for variable
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#2 |
Member
Camilo Costa
Join Date: Jun 2009
Posts: 34
Rep Power: 17 |
Well, I find this variable that should be responsible to evaluate the coefficient of the drag force on the XX direction.
C_DRAG_COEFF_ANISO_XX_IJ(c,t,i,j) But, I dont know what for the index I J are used. Anyone could help me? Thx. Best Regards |
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September 29, 2014, 15:17 |
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#3 |
Member
Camilo Costa
Join Date: Jun 2009
Posts: 34
Rep Power: 17 |
I write this udf, but the problem now is the segmentation violation!! What is wrong? This udf need be written for multiphase problems?
#include "udf.h" /* Define which user-defined scalars to use. */ enum { drag_xx, N_REQUIRED_UDS }; DEFINE_ADJUST(adjust_fcn, domain) { Thread *t; cell_t c; int i = 2; int j = 3; /* Make sure there are enough user-defined scalars. */ if (n_uds < N_REQUIRED_UDS) Internal_Error("not enough user-defined scalars allocated"); /* Fill first UDS with temperature raised to fourth power. */ thread_loop_c (t,domain) { if (NULL != THREAD_STORAGE(t,SV_UDS_I(drag_xx))) { begin_c_loop (c,t) { real drag_xx = C_DRAG_COEFF_ANISO_XX_IJ(c,t,i,j); C_UDSI(c,t,0) = drag_xx; } end_c_loop (c,t) } } } |
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September 29, 2014, 16:26 |
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#4 |
Member
Camilo Costa
Join Date: Jun 2009
Posts: 34
Rep Power: 17 |
I modified the udf just for test the calculation of the scalar variable. And works fine. But now I want to know how the variable is responsible for calculate the drag coefficient of a anisotropic drag model? Anyone who knows?
# include "udf.h" DEFINE_ADJUST(adjust_gradient, mix_dom) { Thread **phase_t; Thread *mix_t; cell_t c; face_t f; int phase_index = 1; /* Fill UDS with the variable. */ mp_thread_loop_c (mix_t,mix_dom,phase_t) { begin_c_loop (c,mix_t) { C_UDSI(c,mix_t,0) = C_VOF(c,phase_t[phase_index]); } end_c_loop (c,mix_t) } mp_thread_loop_f (mix_t,mix_dom,phase_t) { if (THREAD_STORAGE(mix_t,SV_UDS_I(0))!=NULL) begin_f_loop (f,mix_t) { F_UDSI(f,mix_t,0) = F_VOF(f,phase_t[phase_index]); } end_f_loop (f,mix_t) } } DEFINE_ON_DEMAND(store_gradient) { int phase_index = 1; Thread **phase_t; Thread *mix_t; Domain *mix_dom; cell_t c; mix_dom=Get_Domain(1); /* Fill the UDM with magnitude of gradient. */ mp_thread_loop_c (mix_t,mix_dom,phase_t) { begin_c_loop (c,mix_t) { C_UDMI(c,mix_t,0) = NV_MAG(C_UDSI_G(c,mix_t,0)); } end_c_loop (c,mix_t) } } Last edited by camilo_costa; October 2, 2014 at 10:39. |
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drag force, multiphase, plot |
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