CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > STAR-CCM+

*****Easy Question*****

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   June 28, 2013, 16:17
Default *****Easy Question*****
  #1
Member
 
farhad
Join Date: Mar 2010
Location: Tehran
Posts: 32
Rep Power: 7
golriz is on a distinguished road
Hello everybody,
I am new to star ccm+. I have a question about this software.
I should to model 3 different phases (water, solid particles and air) in a hydraulic structure. On the other hand, how can I model a free surface flow of water and solid particles?
Can I model this problem by using star ccm+? If I can, which model must be applied?
Is it possible to apply Eulerian model for simulating of liquid-solid phase?
I hope someone could help me.
Regards,
golriz is offline   Reply With Quote

Old   June 29, 2013, 03:35
Default
  #2
Senior Member
 
siara817's Avatar
 
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 218
Rep Power: 9
siara817 is on a distinguished road
Yes you can model whatever you said. You need to read the tutorial for Eulerian multiphase, you need to define phases, air, solid particles and water. If you have a tank of water, then you may need to use VOF. I recommend you to read tutorial or explain in detail your simulation case.
__________________
Good luck
Siamak
siara817 is offline   Reply With Quote

Old   June 29, 2013, 04:37
Default
  #3
Member
 
farhad
Join Date: Mar 2010
Location: Tehran
Posts: 32
Rep Power: 7
golriz is on a distinguished road
Hi Siamak and thanks for replying. Yes, I have a tank of water and solid particles (sediment). The tank is being used for trapping medium to coarse sediment particles by settling. Water and solid particles inflows to the tank and most of particles are deposited in the tank and a small percentage of particles with water are exited from the outlet of the tank. It should be noted that the flow in the tank is free surface. Now, which model is appropriate for this case? Eulerian or VOF? Can VOF approach be used for solid particles modeling?
Best Regards,
Farhad
golriz is offline   Reply With Quote

Old   July 1, 2013, 05:12
Default
  #4
Senior Member
 
siara817's Avatar
 
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 218
Rep Power: 9
siara817 is on a distinguished road
Hi golriz,

It is a little tricky, when you have a free surface. You have three phases air, water and solid particles. By VOF you can simulate the case of water-air and with DEM you can show the settlement of solid particles in water. I think try one of them and see if it is possible to add the other phase.
For DEM look at this tutorial DEM: Particle Settling.
__________________
Good luck
Siamak
siara817 is offline   Reply With Quote

Old   July 1, 2013, 14:51
Default
  #5
Member
 
farhad
Join Date: Mar 2010
Location: Tehran
Posts: 32
Rep Power: 7
golriz is on a distinguished road
Thanks again for your Replying.
I have another question. Can I model both free surface and settling of solid particles by using Eulerian model? Or by Eulerian I can not predict the free surface?
Farhad
golriz is offline   Reply With Quote

Old   July 2, 2013, 03:33
Default
  #6
Senior Member
 
siara817's Avatar
 
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 218
Rep Power: 9
siara817 is on a distinguished road
To predict the free surface, you need to use VOF. I tried yesterday to test if it is possible to run the Lagrangian multiphase together with VOF. It was possible to select, but I could not see the Lagrangian solver to run. I suggest you to learn first how to run a VOF work on the particle phase. If I found any new thing, I will inform you.
__________________
Good luck
Siamak
siara817 is offline   Reply With Quote

Old   July 2, 2013, 04:17
Default
  #7
Senior Member
 
siara817's Avatar
 
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 218
Rep Power: 9
siara817 is on a distinguished road
Hi golriz,
I used VOF to simulate water and air and then I added a Lagrangian phase for solid particles. It works for steady state case. For transient, it did not work I do not know why.
__________________
Good luck
Siamak
siara817 is offline   Reply With Quote

Old   July 2, 2013, 10:50
Unhappy
  #8
Member
 
farhad
Join Date: Mar 2010
Location: Tehran
Posts: 32
Rep Power: 7
golriz is on a distinguished road
Thanks a lot for suggestion. I try also to model the free surface by Eulerian model, but the solution was diverged.
golriz is offline   Reply With Quote

Old   July 3, 2013, 05:51
Default
  #9
Senior Member
 
siara817's Avatar
 
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 218
Rep Power: 9
siara817 is on a distinguished road
Change the physics to be first order. After iterating until the residual gets uniform, then change one by one to second order.
__________________
Good luck
Siamak
siara817 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 19:46.