Hello
I'm doing a 2D model of a transient incompressible air flow. I have 3 rectangular regions. Actually the central rectangle is intended to represent a porous medium, but I will activate this option when I'll be sure I'm obtaining the right profiles.
So, I put normal inflow velocity as inlet boundary condition and atmospheric pressure asoutlet boundary condition. Other boundaries are defined as walls. Initial pressure was defined as atmospheric pressure and initial velocity as zero.
I've tried several meshes (two of them are shown below). Element quality of all elements in higher than 0.4. I've done studies using differents final times(from 0 to 100 s) , either using user controlled tolerance (0.001; 0.005, etc) and physics controlled tolerance.
My magnitude velocity profile at any constant y for my final time (20 s for example) should be parabolic, because, I mean, it is just a gas flow through a pipe, so normally there is no mistery on it, but I found always the same profile as shown in the picture. This profile shows a higher velocity in some regions near to the wall than in the middle of the rectangle which is obviouslly ilogical.
I'm stuck since several days ago on this problem.
Do you guys have an idea why my profile is always like this??? Any suggestion is welcome.
Thanks in advance, Jhoan.