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-   -   Surface Tension and Capillary Flow (http://www.cfd-online.com/Forums/flow-3d/27246-surface-tension-capillary-flow.html)

CK October 9, 2008 22:48

Surface Tension and Capillary Flow
 
Hi All is anyone using Flow-3D for surface tension + laminar capillary flow modeling? would like to get some advice on how to speed up simulation time.

Rgds CK

AC October 15, 2008 12:01

Re: Surface Tension and Capillary Flow
 
What is limiting the time step? If the surface tension model limits the time step try using the implicit surface tension model.

CK October 17, 2008 01:57

Re: Surface Tension and Capillary Flow
 
Hi AC i did switch to implicit surface pressure solver but time step still around 1e-5. Simulation time is slow (16hrs to reach 2s of simulation time, cell count ~300000) even with SMP version running on 4 CPU cores. so, do you deal with this kind of problem before? i'm looking for any inputs/advice to speed up surface tension & capillary flow problem.

Rgds CK

AC October 17, 2008 11:09

Re: Surface Tension and Capillary Flow
 
Hi CK, I have ran surface tension dominated simulations before. What pressure solver are you using ? GMRES is the best option for most cases. what limits the time step once you switch to implicit surface tension? Is it viscosity? If yes you can try using implicit viscous solver? Also what version of FLOW-3D are you using ? Regards, AC


CK October 18, 2008 08:28

Re: Surface Tension and Capillary Flow
 
Hi AC i'm using setting as below

1. GMRES-implicit-sucessive under-relaxation 2. Surface tension pressure- implicit 3. Advection-Explicit-One fluid,free surface 4. Flow-3D v9.3 SMP with 4 cores.

limiting factor is cx,cy & cz that limit at ~1e-5.

Thus the simulation run slow even with SMP version. So, do you have any good recommendation? Btw, did you used SMP version before? and what is your comments on it?

Rgds CK

Michael Barkhudarov October 18, 2008 13:40

Re: Surface Tension and Capillary Flow
 
Hi CK,

Sounds like it is a very small scale problem, no? Is it possible to simplify the problem: coarsen the mesh, reduce the domain, shorten the time?

CK October 24, 2008 01:52

Re: Surface Tension and Capillary Flow
 
Michael yes this is small scale problem and i already used half symmetry to cut down the mesh size, anyway it is impossible to increase mesh size larger than 1e-4m in order to capture the surface tension correctly. So, do you work with this kind of problem before? is Flow-3D really good in surface tension model?

Rgds CK

Ajayt Thakur February 17, 2009 13:48

Re: Surface Tension and Capillary Flow
 
Dear Sir or Mam

I want to about the experiment of capillarity reaction


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