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James August 5, 2010 16:52

About Brackbill's Continuum Surface Force (CSF) model
I am attempting to use Brackbill's Continuum Surface Force (CSF) model to simulate surface tension in a free-surface flow. For my simulation, the time step constraint imposed by the explicit treatment of surface tension is too tight. The allowable time step is up to the scale of 10^-9 second. Does anyone know any references which use an implicit treatment of surface tension under the framework of CSF? Thanks!


valgrinda August 7, 2010 14:27

Hei James,

I also use the CSF method for free surface flow, but I don't experience such drastic constraints for the timestep. Maybe your code has an error. Depending on your formulation of your Navier-Stokes Equations, you may need to dived the surface tension source term by the density (or multiply with the volume, if you use the finite volume method).

Cheers Hans

James August 9, 2010 12:04

Thank you for your reply! I will double-check my code.


James August 10, 2010 12:12

I noticed that in Brackbill's paper, the average density <Rho> = 0.5*(Rho1 + Rho2). In some other places, this density is taken as a volume averaged value. Which is way is good? Thanks!


valgrinda August 23, 2010 06:09

CSF Implementation
Hei James,

check this paper for the implementation of the CSF model:


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