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mathew May 14, 2007 10:33

Model for Capillary
 
hi,

i am trying to modell a simpel capillary effect. i got a 2D modell from a capillary and want to simulate the water runnig out of region between two pins (like a 3d hole in a surface).i will make it a twophaseflow with freesurface, so the air can fill up the capillary. The mesh is fine enough to represent the expected curvature. Do i have to start with initializing water and the air with 50% volume fraction each in the whole domain and do a steady state run OR initializing with air in the whole flow domain and create water inlet at the sides/top and do transient run?? does cfx model capillary effectes by setting up surface tension and wall adhesion?

thanks a lot

mathew

Gert-Jan May 14, 2007 16:11

Re: Model for Capillary
 
Yes, CFX can handle this. However, you have to include a surface tension and a surface tension model.

Remember that you have to use very small timesteps because surface tension is implemented explicitly.

Gert-Jan

www.bunova.nl

mathew May 15, 2007 04:30

Re: Model for Capillary
 
thank you for your response

ive chosen 5x10^-6 for the timestep so the simulation is taking a long time but i finally reached 6 coeff.lops so that is quite okay with me. I have a free surface flow with two continuous fluids,therefore i only have a "Continuum Surface Force" and a primary fluid which is water in my case. Actually i am doing a singel-bubble-evaporating at a wall and now i am trying to include more and more physical forces.

mathew


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