{"id":28826,"date":"2018-03-05T22:02:21","date_gmt":"2018-03-05T22:02:21","guid":{"rendered":"\/forum\/forums\/topic\/hooking-uds-to-the-model\/"},"modified":"2018-03-05T22:02:21","modified_gmt":"2018-03-05T22:02:21","slug":"hooking-uds-to-the-model","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/hooking-uds-to-the-model\/","title":{"rendered":"Hooking UDS to the model"},"content":{"rendered":"

Hello everyone,<\/p>\n

<\/p>\n

I have been interpreting some User-defined functions, and now I would like to use User defined scalars. Quite a lot of people use them, yet the documentation is not that clear about the steps to follow. Basically, after interpreting, when I launch the calculation, Fluent crashes and closes. I don’t have time to see what kind of error it is, but I think it is written: MPI error.<\/p>\n

<\/p>\n

I will describe the steps I use, hoping it would help others.<\/p>\n

<\/p>\n

Step 1: Writing the UDF in a .c file<\/p>\n

<\/p>\n

\/* Defining the adsoprtion of the system *\/ \/********************************************\/<\/p>\n

#include “udf.h”<\/p>\n

int ads;<\/p>\n

DEFINE_ADJUST(adsorption,domain){
Thread*t; cell_t c; real E,A,P;
thread_loop_c(t,domain){
begin_c_loop (c,t){
real tem=C_T(c,t);
P=C_P(c,t)+RP_Get_Real(“operating-pressure”);
E=3080+18,9*tem;
A=8,31429*tem*log(1.47E9\/P);
C_UDSI(c,t,ads)=71.6*exp(-A*A\/(E*E));}
end_c_loop(c,t)}
}<\/p>\n

        DEFINE_SOURCE(energy_source,c,t,dS,eqn){
            real e_source;
            e_source=-C_UDSI_M1(c,t,ads)*0.496056352e3*3080*sqrt(log(71.6\/C_UDSI_M1(c,t,ads)));
            dS[eqn]=0.0;
            return e_source;
        }<\/p>\n

<\/p>\n

 Step 2: Interpreting the UDF<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

Step 3: Adding a User Defined Scalar (UDS)<\/p>\n

<\/p>\n

In Flux function, I chose Adsorption, corresponding to the UDF using the UDS<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

Step 4: Hooking the UDF<\/p>\n

<\/p>\n

I hooked adsorption as an adjust function<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

Step 5: In Cell Zone condition>cross Source>Source>Energy source> Choose UDF energy_source.<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

Step 6: Initializing. Everything ok (hybrid initialization)<\/p>\n

<\/p>\n

Step 7: Running calculation. When it comes to the first iteration, Fluent crashes. Infortunately, I don’t have time to take a screenshot.<\/p>\n

<\/p>\n

Where does it come from? Did I forget a step or something in the programme?<\/p>\n

<\/p>\n

Regards,<\/p>\n","protected":false},"template":"","class_list":["post-28826","topic","type-topic","status-closed","hentry"],"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