{"id":319002,"date":"2023-11-22T10:23:50","date_gmt":"2023-11-22T10:23:50","guid":{"rendered":"\/forum\/forums\/topic\/udf-crash\/"},"modified":"2023-11-22T10:23:50","modified_gmt":"2023-11-22T10:23:50","slug":"udf-crash","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/udf-crash\/","title":{"rendered":"UDF crash"},"content":{"rendered":"

I tried to calculate the stockes number for a specific group of particles. here is the code.<\/p>\n

This udf has been hooked up in DPM model and the number of scalar is set to 1.<\/p>\n

<\/p>\n

<\/p>\n

the code has no compiling issue in this LES case. the case runs on HPC with 128 cores. memory info is listed below.<\/p>\n

 <\/p>\n

<\/p>\n

but when the calculation started, then it crashed.<\/p>\n

 <\/p>\n

#include “udf.h”<\/div>\n
#include “dpm.h”<\/div>\n
 <\/div>\n
DEFINE_DPM_SCALAR_UPDATE(StokesNumber,c,t,init,p)<\/div>\n
{<\/div>\n
    cphase_state_t *cp;<\/div>\n
    cp = p->cphase;<\/div>\n
    \/* cphase_state_t *c = &(p->cphase); *\/<\/div>\n
 <\/div>\n
    real tau_p = 0;<\/div>\n
    real drag_factor;<\/div>\n
    real tau_f = 1e-16;<\/div>\n
    real C_mu = 0.09;<\/div>\n
    real l_int, u_f; <\/div>\n
 <\/div>\n
    \/* Compute particle relaxation time *\/<\/div>\n
    if (P_DIAM(p) != 0.0)<\/div>\n
    {<\/div>\n
tau_p = P_RHO(p)*pow(P_DIAM(p), 2.0)\/C_MU_L(TP_CELL(p), TP_CELL_THREAD(p));<\/div>\n
drag_factor = DragCoeff(p); \/* returns 18*Cd*Rep\/24 ? Please check *\/<\/div>\n
tau_p \/= drag_factor;<\/div>\n
    }<\/div>\n
    else<\/div>\n
    {<\/div>\n
tau_p = 0.;<\/div>\n
    }<\/div>\n
 <\/div>\n
    \/* Compute the fluid time scale<\/div>\n
       (based on integral length scale) *\/<\/div>\n
    if (C_D(TP_CELL(p), TP_CELL_THREAD(p)) > 0)<\/div>\n
    {<\/div>\n
        l_int = C_mu*pow(C_K(TP_CELL(p), TP_CELL_THREAD(p)), 1.5)\/C_D(TP_CELL(p), TP_CELL_THREAD(p));<\/div>\n
    }<\/div>\n
    else<\/div>\n
    {<\/div>\n
l_int = 1.;<\/div>\n
    }<\/div>\n
    <\/div>\n
    \/* Velocity magnitude*\/<\/div>\n
    u_f = sqrt(pow(cp->V[0], 2.0) + pow(cp->V[1], 2.0) + pow(cp->V[2], 2.0));<\/div>\n
 <\/div>\n
    if (u_f > 1e-12)<\/div>\n
    {<\/div>\n
tau_f = l_int\/u_f;<\/div>\n
    }<\/div>\n
     else<\/div>\n
    {<\/div>\n
tau_f = 1.;<\/div>\n
    }<\/div>\n
 <\/div>\n
    \/* Stokes Number *\/<\/div>\n
    P_USER_REAL(p,0) = tau_p \/ tau_f;<\/div>\n
 <\/div>\n
}<\/div>\n

<\/p>\n","protected":false},"template":"","class_list":["post-319002","topic","type-topic","status-closed","hentry","topic-tag-dpm","topic-tag-les","topic-tag-particle-tracking","topic-tag-udf"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t