porous media in FLUENT
Hi everybody,
I'm simulating flow through porous media and it works well with FLUENT. However, I have a question concerning the theory behind the flow: Basically, two different formulations can be used, one is denominated the "superficial velocity formulation" and the other one is the "physical velocity formulation". In the superficial velocity formulation, a sink term is added the usual momentum equation, S = mu/alpha * v (in my model I neglect the inertia resistance) mu is the dynamic viscosity, v the velocity and alpha denotes the permeability. However, the solution changes (as it should) if I use different values for the porosity gamma. I now wonder where the porosity enters the model equations within the superficial velocity formulation? As far as I know, the permeability does not depend on the porosity, however, in the ANSYS FLUENT 12.0 Users-Guide - 7.2.3, I find the following statement: " Both K and C2 are functions of (1-gamma). " What kind of relation is that and how is it theoretically justified? Thank you for any piece of advice, Natalie |
So FLUENT does assume that the permeability depends on the porosity and modifies the value of 1/alpha accordingly?
Thanks for your answer, Natalie |
No, you have to set the value of permeability yourself as a part of your physics setup. FLUENT is just a solver, that solves your setup.
The gist of my post above was that both the permeability and inertial coefficient of resistance depend on porosity. OJ |
I understand, thank you!
Natalie |
Dear Natalie and OJ,
I would appreciate if either of you would answer this issue. The original question of Natalie which led me also to this thread, is still not answered. Also defining Zeta and other coefficients would involve porosity, but ignoring the loss coefficient and making C2=0, will leave our momentum sinkterm as (miu/permeability)*Velocity. Assume that permeability is a constant number here. Why CFX is still asking for porosity? Why changing the porosity will change the simulation results as Natalie said, although it is not in our equations? |
Hi every body
I don't know how determine initial velocity for the flow in porous media. Thank you for time and consideration. Best regards |
hello
first: i want to say thank you for your guids about porous resistance .but i dont undrestant that how can i calcculet viscous and inertial resistans. secund :I am working on porpous media problem (heat transfer) but i cant find a good tutorial about heat transfer into porous media also i want to use source term in my problem. Thanks for your answer |
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