[Infobiz]

Hi,

I'm a master student under graduation. My current thesis work is on fictitious methods and I am trying to implement it in Fluent (v17.2). In particular I account for solid objects using the permeability (K) and porosity of cells. Solid cells has K=10^12 while fluid cells K=10^-10, the porosity instead is 1 and 0 (tried 0.0001 too) for solid and fluid cells respectively. As numerical methods I am using PRESTO! for pressure and second order for momentum and tried our SIMPLE, SIMPLEC and PISO scheme.
My geometry is a simple cylinder (d=0.4) immersed in a fluid (domain L=2m, H=1m) , I use pressure-inlet, outlet and symmetry boundary conditions.

In all conditions I get this errors on pressure field (see attachment), velocity field is instead correct beside velocity vectors.

To impose the cell zone condition I use interpreted UDF that imposes the profile of permeability and porosity on the whole domain.

Do any of you ever worked on this method in fluent or know how to resolve this pressure issue?

Thank you for the help,
Walter

[Infobiz]

I forgot to mention that I am using a uniform Cartesian mesh with up to 240 elements per edge (57.600 cells). I already performed a grid sensitivity analysis but that is not the problem unfortunately. I tried with different boundary conditions too, periodic mass flow rate and velocity inlet, the problem persists.

I believe the cause is the high jump in permeability, but a conference paper ( see P.S.) I am trying to follow reports the results for the same problem and they don't have these problems.

P.S. conference paper link
https://www.researchgate.net/publica...3D%3D&el=1_x_2