[Qkarl]

Hi all,

I was trying to simulate the pressure drop thru a porous media 2D using fluent, and initially i tried with porous zone setting with cell zone set as porous zone. The result seems good.
Next, i want to simply the simulation, by using porous jump setting with the same C2 & permeability at internal boundary, but my solution diverged.

I had try to increase my inlet air velocity / decrease the permeability, and i able to get converged solution. So, i think it might due to the pressure drop at porous jump too high, and the solution couldnt converge.

What across my mind was, i able to get the converged result using same setting using porous zone, but why i couldnt get it using porous jump simulation? anyone can help with this? thanks alot

[vinerm]

Since the porous jump condition is applied on an interior boundary, user needs to provide an appropriate value for the thickness. If you use same thickness as that for original porous zone, then the same values for the coefficients should work alright. However, in one case it expects reciprocal of the other. I suppose porous jump expects direct value of while in porous zone value of is expected.

[Qkarl]

Yes, the thickness input was same as the porous zone thickness, which the permeability (m2) also input correctly for porous jump, inverse of it in porous zone. But the solution is still diverged in porous jump setting.

[vinerm]

If the physical setup is correct, then it could only numerics (including mesh quality). If mesh is good, then try to resolve the issue by using first-order numerics. Furthermore, you may try to start with larger value of permeability and smaller value of porous jump coefficient and then increase those slowly.