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Porous-Fluid Interface Treatment

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Old   October 2, 2019, 14:57
Question Porous-Fluid Interface Treatment
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Farhad.a
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Hello,

I have simulated a 3D air channel partially filled with porous media and examined the pressure drop and heat transfer in this channel. For the porous zone Forchheimer extended Darcy’s equation and the thermal equilibrium model have been employed and the flow has been considered as laminar flow, but for the fluid cell zone the flow is turbulent and RNG k-Epsilon turbulence modeling has been utilized.
The question is how two sets of governing equations are solved and how the interface between the domains (where each of these governing equation is applicable) is handled?

I mean i know there are different interface conditions such as The Ene, Levy and Sanchez-Palencia interface, The Beavers-Joseph interface, but i want to know which interface conditions does ANSYS Fluent use if i haven't selected one.
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Old   October 2, 2019, 15:36
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Lucky Tran
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I don't think there is any special interface treatment.

When you select the laminar zone option, Fluent sets the turbulent production in that zone to zero. The variables (k, epsilon, etc.) are still transported through the laminar zone.

There is another option (accessed using TUI commands) that allows you to also set the turbulent viscosity to zero in the laminar zone. But again, they are simply transported.
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Old   October 3, 2019, 02:26
Unhappy Porous interface
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Thanks for your reply.
But, there are extra terms in the momentum equation for the porous zone, the governing equations are completely different. I found just Porous jump treatment which is for 2D simulations and not the case for the 3D simulation that i've done.
I don't usually care about these equations, but the reviewer of the article that i've submitted has asked this question, and i have to answer it to submit the revised manuscript: "how two sets of governing equations are solved and how the interface between the domains (where each of these governing equation is applicable) is handled?"
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Old   October 3, 2019, 02:27
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Thanks for your reply.
But, there are extra terms in the momentum equation for the porous zone, the governing equations are completely different. I found just Porous jump treatment which is for 2D simulations and not the case for the 3D simulation that i've done.
I don't usually care about these equations, but the reviewer of the article that i've submitted has asked this question, and i have to answer it to submit the revised manuscript: "how two sets of governing equations are solved and how the interface between the domains (where each of these governing equation is applicable) is handled?"
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Old   October 3, 2019, 03:52
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The pressure drop due to the porous media is handled by adding an extra volumetric momentum sink. If you need a reference, refer to the user manual section on Porous Media Conditions (see 7.2.1-3).

There is only one momentum equation. Refer to my previous post for why there is only one momentum equation when you use a laminar zone option. Interface treatment is needed in general when you actually have two separate sets of governing equations. But that is not the case.

Last edited by LuckyTran; October 3, 2019 at 12:14.
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Old   October 3, 2019, 07:20
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Again, Thanks for your reply.
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porous baffle interface, porous boundary, porous cell zone, porous domain, porous formulation

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