CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   unsteady DPM and steady flow (http://www.cfd-online.com/Forums/fluent/79254-unsteady-dpm-steady-flow.html)

Mohsin August 18, 2010 04:16

unsteady DPM and steady flow
 
I have unsteady DPM and steady flow but after 4000 iterations when solution converges. The particle fate is empty. I cant see any particle tracked. why it is so. Please explain.

xrs333 August 18, 2010 04:44

Hi,
Is the number that follows 'tracked=' reported in the console zero, too?

Mohsin August 18, 2010 04:45

hi

No. its not. Its just not displaying any number. only writing fate and mass flux labels.

thanks

xrs333 August 18, 2010 05:09

Hi, Mohsin,
Have you set petinent start time and stop time for the injection?

Mohsin August 18, 2010 05:15

It is steady state for the air flow but for DPM the particles will enter into the domain at t=8 seconds and will be injected until t=16 seconds. so i gave the particle strat andend time as 8 to 16 respetively.

The time step size was given as =0.5
and total number of time steps was=50

because the particles are large so i though to give the step size as 0.5 (which means after every 0.5 seconds the assigned number of particles will be injected) and the time period for the particles to stay in the domain was 5 seconds in steady case so 0.5/5=10 gives me the number of time steps for 1 period (i-e when the particles will move from inlet and captured at the outlet) so then i assumed 50 total number of time steps for my case so that i could simulate for 5 periods.

What could be wrong?

xrs333 August 18, 2010 05:22

I think all the particles injected during t=8~16s have escaped from the domain after some time steps of iteration.

souria October 9, 2014 05:30

Hey Mohsin,
What did you call by "Period" here ?? And what does represent "5s" ? I m in the same case as you, and Im tryning to undersatnd the meaning of each parameters (number time step, particle time step size, start time, stop time..)


All times are GMT -4. The time now is 19:03.