DPM Output Parameter UDF

Eanna.Kennedy · January 30, 2019, 10:25

Hello,

I am trying to optimise a channel geometry using particle tracking. I want to minimise the standard deviation of particles about the centre of the channel at a plane near the outlet.

I think that i need to use the DEFINE_REPORT_DEFINITION_FN macro to calculate and return the standard deviation of particles. But to do this i need to have access to the positions of all particles as they cross this plane.

I know that the DEFINE_DPM_OUTPUT macro is used to write particle data to a file when I perform particle trajectory sampling with a plane.

But i can't figure out how to access the particle position data so that I can calculate the standard deviation. So either I need a way to read data from the .dpm file generated by sampling or I need to alter the DEFINE_DPM_OUTPUT macro to save data to a User Defined Memory, but it seems that this macro is called each time a particle passes the sampling plane so I don't see how I could save each particles data in the UDM without overwriting the last.

I would really appreciate any help with this.

Kind Regards,
Eanna Kennedy

Amir Soly · July 12, 2020, 07:30

Hello Eanna,
I have exactly the same problem,
Could you find a solution?

AlexanderZ · July 13, 2020, 02:21

Ansys Fluent Customization manual, Model-Specific Macros chapter

P_POS(p)[i] is a macro to get position of particle

January 30, 2019, 10:25	DPM Output Parameter UDF	#1
Eanna.Kennedy New Member Eanna Kennedy Join Date: Jan 2019 Posts: 4 Rep Power: 7	Hello, I am trying to optimise a channel geometry using particle tracking. I want to minimise the standard deviation of particles about the centre of the channel at a plane near the outlet. I think that i need to use the DEFINE_REPORT_DEFINITION_FN macro to calculate and return the standard deviation of particles. But to do this i need to have access to the positions of all particles as they cross this plane. I know that the DEFINE_DPM_OUTPUT macro is used to write particle data to a file when I perform particle trajectory sampling with a plane. But i can't figure out how to access the particle position data so that I can calculate the standard deviation. So either I need a way to read data from the .dpm file generated by sampling or I need to alter the DEFINE_DPM_OUTPUT macro to save data to a User Defined Memory, but it seems that this macro is called each time a particle passes the sampling plane so I don't see how I could save each particles data in the UDM without overwriting the last. I would really appreciate any help with this. Kind Regards, Eanna Kennedy Amir Soly likes this.

July 13, 2020, 02:21		#3
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	Ansys Fluent Customization manual, Model-Specific Macros chapter P_POS(p)[i] is a macro to get position of particle __________________ best regards ****************************** press LIKE if this message was helpful

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July 12, 2020, 07:30		#2
Amir Soly New Member Amirmohamad Join Date: Jul 2020 Posts: 1 Rep Power: 0	Hello Eanna, I have exactly the same problem, Could you find a solution?