[Darius12345]

Hello Everyone,

I am trying to create an optimization setup with Fluent and Design Xplorer where the radial particle distribution is an input parameter for the optimization. So I want to get the x and y position of each particle when it is at a specified plane (or z-position), calculate the radius from it, and see if it is above or below a given radius. The output parameter is then the share of particles above this radius.

I first tried with DEFINE_DPM_OUTPUT to get the x and y position of my particle and then store it in a file, I then read the file back in and create an output parameter using DEFINE_REPORT_DEFINITIN_FN but the file is only updated when a sample is created, which is not useful for my problem, or is it possible to create a sample every few iterations automatically?

My current approach is a SCALAR_UPDATE-UDF, where the positions are stored in the TP_USER_REAL array for each particle, here the data should be updated after each DPM iteration. The array is then read back to create an output parameter with DEFINE_REPORT_DEFINITION, both UDFs compile but when I start simulating I am getting a SIGSEV error. If I only use the SCALAR_UPDATE_MACRO everything is working. You can see my code in the attached picture.

If you have any suggestions on how to solve this issue, your help is much appreciated, also I am not quite sure if I can call DPM functions within non-DPM UDFs, is this possible at all?

Thanks in advance for your help.

[AlexanderZ]

next time put your code here as a text, not picture

I don't have a lot experience in DPM simulations
but what can i suggest is:
1. SIGSEV error means you have problems with memory, you are trying to access something, which doesn't exit

2. Most likely you have problems with loops:
loop (I,Ilist)
{
loop(tp, I)
{

3. what I can see in your code, Ilist is defined using Ilist = get_dpm_injection() macro
But I is not defined

4. tp is not defined either in your code

5. So you may try to use only one loop with defined injecttion and particle pointers:

loop(tp,Ilist->tp)

[Darius12345]

Hello AlexanderZ,

thank you for the reply, I thought the pointers are defined with Injection *I and Tracked Particle *tp. Also when I tried to define I and tp as integer I get error messages that these variables are already defined. Is there a way to define them like Ilist with something like get_dpm_particles()?

My explanation for the SIGSEV was that TP_USER_REAL is not available in the REPORT_DEFINITION Macro?

[AlexanderZ]

change

loop (I,Ilist)
{
loop(tp, I)
{

to

loop(tp,Ilist->tp)

[Darius12345]

Thanks again, I tried with your loop but now I get the following error:

error: no member named 'tp' in 'struct injection_struct'
loop (tp,Ilist->tp)

In the meantime I tried with global variables instead and this 2 UDFs are also compiling fine, the simulation is running (without the Messages) but my output for "a" is always 1. When I insert the mesages the DPM iterations does not finish, so I can not check if 'i' and 'j' are increased correctly. Any suggestions on why this is not working?

I tried with different DPM Setups, for my understanding if I use 'Interaction with continuous phase' or transient particle tracking the SCALAR_UPDATE Macro should be called whenever the particles are calculated and then my output parameter should also change.

#include "udf.h"

float i = 1.0;
float j = 1.0;

DEFINE_DPM_SCALAR_UPDATE(sampling_pos,cell,thread,initialize,tp)
 {
    float r = 0.0;
    if (initialize)
     {

     }
    else
     {
           r = sqrt(SQR(TP_POS(tp)[0])+SQR(TP_POS(tp)[1]));
           /*Message("r= %d\n", r);*/
           i = i + 1;
           /*printf("i= %i\n", i);*/
           if (r > 0.09)
           {
            j = j + 1;
            /*printf("j= %i\n", j);*/
           }
      }
 }

DEFINE_REPORT_DEFINITION_FN(positions)
 {
  float a = 0.0;
  a = j / i;
  return a;
 }

[Darius12345]

Hello,

I was able to solve the issue by creating a sample file automated after n iterations using 'execute commands' in the Solution > Activities > Create Tab. Then I used DEFINE_DPM_OUTPUT to write the desired data at these points and read it back in with a UDF for an output parameter.

Thanks for your suggestions, I will mark this Question as solved then.