[Mojtaba.a]

Hi,

I am rather new to DPMFoam. I wanted to simulate a very simple T-Junction problem, in which there is one inlet and two outlets.

You can see the images. The first image is done using icoFoam, and there is no problem in here.

The second image is using DPMFoam, I have disabled the coupling between the continuous phase and particles.

I am focusing on the continuous phase. But I can not get the results obtained previously by icoFoam.

What am I doing wrong?

You can get the DPM case from the link below:

https://www.dropbox.com/s/726lc9bdt3...PM.tar.gz?dl=0


Thanks,
Mojtaba.

[Mojtaba.a]

Are there any suggestions ?!

I just want to make similar results to icoFoam using DPMFoam in which I have disabled all particle forces.
I am trying to first validate the results obtained by solving fluid equations and then solving for particles.

I would really appreciate if somebody could help.
Thanks.

[maysmech]

Originally Posted by Mojtaba.a

Are there any suggestions ?!

I just want to make similar results to icoFoam using DPMFoam in which I have disabled all particle forces.
I am trying to first validate the results obtained by solving fluid equations and then solving for particles.

I would really appreciate if somebody could help.
Thanks.

Hi,
Check the kinematic viscosity and density of fluid phase.
The reason behind the unrealistic result is gravity effect on fluid. When I turned off the gravity the result was ok, so it is because of 1) small inlet velocity magnitude, 2) viscous and dense fluid phase
You didn't send the icoFoam case but I think you used air properties there and are using something like water properties here.

[Mojtaba.a]

Originally Posted by maysmech

Hi,
Check the kinematic viscosity and density of fluid phase.
The reason behind the unrealistic result is gravity effect on fluid. When I turned off the gravity the result was ok, so it is because of 1) small inlet velocity magnitude, 2) viscous and dense fluid phase
You didn't send the icoFoam case but I think you used air properties there and are using something like water properties here.

Thank you for your fast response.

Well, you were right. All I wanted to do was to disable gravity. I am getting nice results now.

Regarding the kinematic viscosity and density of the fluid, I am not using air nor water properties for my simulation. Actually I am trying to simulate a very viscous fluid.

There is another question I have. By disabling gravity I have disabled the weight force induced on both fluid and particles. How can I include the weight force on particles and not on the fluid phase?

Thank you,
Best.

[maysmech]

Originally Posted by Mojtaba.a

Thank you for your fast response.

Well, you were right. All I wanted to do was to disable gravity. I am getting nice results now.

I didn't suggest to turn off gravity to reach true answer. It was a trick to find the source of difference between icoFoam and DPMFoam results. So If you want compare both solvers you need to use similar properties, especially the density.