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March 3, 2021, 08:21 
UDF in case with DPM modle

#1 
New Member
MengqiangHu
Join Date: Feb 2019
Posts: 13
Rep Power: 5 
Hi, all
I am trying to get the particle numbers in each cell and then calculate the particle concentration in each cell. I have used a UDF, which contains the loop(I, Ilist), loop(p,I>p), C_UDMI, and so on. After the calculation, I have check the contour of C_UDMI_0 and C_UDMI_1, they are similar to the contour of the DPM parcels or particles. However, when I want to write the C_UDMI of each cell to a exernal txt file, there are some problems. In my case, the whole flow field is consisted by two zones, i.e., fluid 1 and fluid 2. There are 124800 cells in each fluid zone. In the outputed txt file, only the cells in fluid 1 were considered, and the UDF outputs these cells again and again. I wonder what happened and what should I do to get a right way to output these data. Thanks a lot. My UDF file is attached. Code:
#include "udf.h" DEFINE_ADJUST(particle_cells_count,d) { if ((CURRENT_TIME==0)(CURRENT_TIME==0.01)) { Thread *t; char filename[256]; Injection *Ilist; Injection *I; Particle *p; cell_t c; Thread *c_t; int parcel_trapped = 0; real num_particles=0.; real num_particles_in_total=0.; real number_in_parcel=0.; Ilist = Get_dpm_injections(); loop(I, Ilist) { loop(p, I>p) { c = P_CELL(p); c_t = P_CELL_THREAD(p); parcel_trapped+=1; num_particles=p>number_in_parcel; C_UDMI(c,c_t,0)=C_UDMI(c,c_t,0)+1.; C_UDMI(c,c_t,1)=C_UDMI(c,c_t,1)+num_particles; num_particles_in_total=num_particles_in_total+num_particles; num_particles=0.; Message("num_particles_in_total: %f",num_particles_in_total); Message("parcel_trapped: %d",parcel_trapped); //Message("pacel %d is in cell %d\n",parcel_trapped,c); //Message("There are %f particles in parcel %d\n",num_particles,parcel_trapped); } } FILE *fpwrite; thread_loop_c(t,d) { begin_c_loop(c,c_t) { sprintf(filename,"parcelsconcenincells%f.txt",CURRENT_TIME); fpwrite= fopen(filename,"a+"); if (fpwrite == NULL) { return 0; } fprintf(fpwrite,"There are %f parcels in cell %d \n",C_UDMI(c,c_t,0),c); fclose(fpwrite); char filename[256]; sprintf(filename,"particlesconcenincells%f.txt",CURRENT_TIME); fpwrite=fopen(filename,"a+"); if (fpwrite == NULL) { return 0; } fprintf(fpwrite,"There are %f particles in cell %d \n",C_UDMI(c,c_t,1),c); fclose(fpwrite); } end_c_loop(c,c_t) } } } There are 19.414102 particles in cell 0 There are 26.287837 particles in cell 1 There are 29.934247 particles in cell 2 There are 26.287837 particles in cell 3 There are 19.414102 particles in cell 4 There are 23.331015 particles in cell 5 There are 30.204750 particles in cell 6 There are 33.851161 particles in cell 7 ...... There are 36.954978 particles in cell 124790 There are 53.476081 particles in cell 124791 There are 62.240273 particles in cell 124792 There are 53.476081 particles in cell 124793 There are 23.331016 particles in cell 124794 There are 19.414101 particles in cell 124795 There are 26.287835 particles in cell 124796 There are 29.934246 particles in cell 124797 There are 26.287835 particles in cell 124798 There are 9.707051 particles in cell 124799 There are 19.414102 particles in cell 0 There are 26.287837 particles in cell 1 There are 29.934247 particles in cell 2 There are 26.287837 particles in cell 3 There are 19.414102 particles in cell 4 There are 23.331015 particles in cell 5 There are 30.204750 particles in cell 6 There are 33.851161 particles in cell 7 There are 30.204750 particles in cell 8 There are 23.331015 particles in cell 9 There are 27.152663 particles in cell 10 There are 34.026397 particles in cell 11 There are 37.672808 particles in cell 12 ...... My flow field is shown in the attached picture. Thanks a lot! 

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