DPM-SteadyFlow-About Stop/Stard Time Properties and Particle Time Step Size

souria · October 8, 2014, 11:33

Hey everyone,
What is exact meaning of stop time in the set injection properties in the fluent under define injection ?
I'm simulating sediment transport (in river) for a STEADY FLOW. In case, I choose "Unsteady Particle Tracking" , these parameters refer to what step ? What time ?

Start time, Stop Time
The Particle Time Step size
Number of time Steps
Max. Number of steps
Step Length

Are these parameters depending on the time of calculation ? or on the number of the iterations ?

Thanks for your help

Souria

diamondx · October 8, 2014, 23:43

Hi souria,
When the DPM (discrete phase model) is activated, The calculation related to your particles are not solved in the same time as your gasous domain. the two calculation are done separately. Fluent solves your flow for a certain given iterations (that you provided), then makes a pause to use calculated properties in the DPM calculation. Therefor, you can solve your gaseous domain in a steady state fashion, and the DPM in a transient fashion. You have to understand that the two calculation are done separately. and since the dpm is in a transient fashion, obviously you have to set a time step, start and stop time. I hope I was clear

souria · October 9, 2014, 03:36

Thans for your answer, If I'd really get it, you mean there's no relationship between the number of iterations (Im in steady flow, so the calculation is just gouverned by itérations and no time step...) and the Time step that we choose to solve the DPM.

October 8, 2014, 11:33	DPM-SteadyFlow-About Stop/Stard Time Properties and Particle Time Step Size	#1
souria Member souria Join Date: Mar 2013 Location: Nancy Posts: 66 Rep Power: 13	Hey everyone, What is exact meaning of stop time in the set injection properties in the fluent under define injection ? I'm simulating sediment transport (in river) for a STEADY FLOW. In case, I choose "Unsteady Particle Tracking" , these parameters refer to what step ? What time ? Start time, Stop Time The Particle Time Step size Number of time Steps Max. Number of steps Step Length Are these parameters depending on the time of calculation ? or on the number of the iterations ? Thanks for your help Souria

October 8, 2014, 23:43		#2
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	Hi souria, When the DPM (discrete phase model) is activated, The calculation related to your particles are not solved in the same time as your gasous domain. the two calculation are done separately. Fluent solves your flow for a certain given iterations (that you provided), then makes a pause to use calculated properties in the DPM calculation. Therefor, you can solve your gaseous domain in a steady state fashion, and the DPM in a transient fashion. You have to understand that the two calculation are done separately. and since the dpm is in a transient fashion, obviously you have to set a time step, start and stop time. I hope I was clear sharonyue and aminbayat like this. __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
particle time step size, number of time steps in DPMPM	lili	FLUENT	25	August 25, 2017 08:36
cyclone separator particle tracking prob..	sakurabogoda	CFX	33	May 29, 2013 06:36
error message	cuteapathy	CFX	14	March 20, 2012 06:45
URGENT - DPM Particle Properties	Sandilya Garimella	FLUENT	1	March 5, 2008 14:19
Two-Phase Buoyant Flow Issue	Miguel Baritto	CFX	4	August 31, 2006 12:02

October 9, 2014, 03:36		#3
souria Member souria Join Date: Mar 2013 Location: Nancy Posts: 66 Rep Power: 13	Thans for your answer, If I'd really get it, you mean there's no relationship between the number of iterations (Im in steady flow, so the calculation is just gouverned by itérations and no time step...) and the Time step that we choose to solve the DPM.