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Modifying Darcy's Law

Posted Feb 3, 2012, 2:27 a.m. EST Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2 0 Replies

John Davidson
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Hi
I'm trying to model the effect of osmotic pressure using Darcy's Law in Comsol 4.2.
As it stands the equation is
d(rho*epsilon_p)/dt + grad(-rho/mu* kappa * div(p) ) = 0

I'd like to augment the equation so that the last term on the left hand side was div( p - OS)
where OS is my calculated osmotic pressure.
I've already tried placing the terms d(d(OS,x),x)+d(d(OS,y),y) on the right hand side using the 'mass source' option, however this seemed to create numerical problems (not surprising for a double derivative of a variable I suppose..)

Any thoughts? I'm realtively new to comsol, so sorry if this is a stupid question.
Cheers
John
0 Replies Last Post Feb 3, 2012, 2:27 a.m. EST
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