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Hello Rohini Bala Chandran

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Also my solver doesn't converge (Image attached) with this physics.

The error message is:
"Failed to find a solution.
Divergence of the linear iterations.
Returned solution is not converged."

My problem is to simulate the flow of air through a square channel and a porous solid (SiC).

I'm trying to use the physic "Free and Porous Media Flow" (Domain: All)

- Fluid Properties (Domain: All, pressure fp/fp1)
- Porous Matrix Properties (Domain: 1, Porous Material SiC, Porosity 0.5, Permeability e-10)
- Inlet (5m/s)
- Outlet (P=0)
- Initial value (P=0 u=0)

Are these settings and boundary conditions correct?

Hi

for diffusion equations it's often the intial conditions (default all =0) that are too far from the solution for the solver to converge. try to initiate flow and diffusion equations in the initial conditions, or try running a steady state with low flow velocity and ramp up any flow with a parametric sweep or over the first seconds/hours of yout time/transient simualtion

--
Good luck
Ivar

Hi Ivar,

I initialize the flow with a velocity as 0.1 in the axial direction as you suggested to me and it works with a permeability of 1e-10 m2 (Permeability_1e-10.png.png)

In every way the velocity slices don't show flow in the porous media around the open channel. (velocity_Permeability_1e-10.png)

First of all I tried to change the permeability, but as I increase it the system doesn't converge (Permeability_1e-9.png).

My second solution was to insert a solid cubic obstacle in the free channel to force the fluid to go through the porous media. As the fluid approaches the obstacle the velocity goes to zero, but inexplicably v goes to zero in the porous wall to recover it's value after passing the cubic. (Cubic obstacle.png)

How is it physically possible?
What is wrong with my settings?

Thank you for your support.

Hi,

Have you been able to figure this out? I am also having problems simulating flow through a porous media. I am using Free and Porous Media Flow, and cannot get the flow to go through a foam media. The flow simply goes around it.

Thank you in advanced for any help you can provide,
Alfredo

When I am using the "free and porous flow" model, I also sometimes have results where the velocity is zero within the porous media. However, when you look at the pressure, you see that there is a flow through the porous part because you can see a pressure drop over this area. I dont know how this is possible in the equation (since pressure is linked to velocity) but it happens.

I found, that the reason for this problem is, for the most part, a coarse mesh. By refining the mesh, the velocity increases to a certain value. Interestingly, the pressure drop stays alsmost constant, so the calculation of the pressure does not really depend on the velocity within the porous part.

So I suppose you should try to use a finer mesh for the calculation to see if the reults change.