About Brackbill's Continuum Surface Force (CSF) model

James · August 5, 2010, 17:52

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!

James

valgrinda · August 7, 2010, 15:27

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, 13:04

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

James

James · August 10, 2010, 13:12

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!

James

valgrinda · August 23, 2010, 07:09

Hei James,

check this paper for the implementation of the CSF model:
http://wissrech.ins.uni-bonn.de/rese...er/droplet.pdf

Regards
Hans

August 5, 2010, 17:52	About Brackbill's Continuum Surface Force (CSF) model	#1
James New Member James Zhong Join Date: Mar 2009 Posts: 25 Rep Power: 17	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! James

August 7, 2010, 15:27	Csf	#2
valgrinda Super Moderator Hans Bihs Join Date: Jun 2009 Location: Trondheim, Norway Posts: 403 Rep Power: 19	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

August 23, 2010, 07:09	CSF Implementation	#5
valgrinda Super Moderator Hans Bihs Join Date: Jun 2009 Location: Trondheim, Norway Posts: 403 Rep Power: 19	Hei James, check this paper for the implementation of the CSF model: http://wissrech.ins.uni-bonn.de/rese...er/droplet.pdf Regards Hans

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August 9, 2010, 13:04		#3
James New Member James Zhong Join Date: Mar 2009 Posts: 25 Rep Power: 17	valgrinda, Thank you for your reply! I will double-check my code. James

August 10, 2010, 13:12		#4
James New Member James Zhong Join Date: Mar 2009 Posts: 25 Rep Power: 17	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! James