[Chander]

Hi,

I have simulated a single phase water flow with both kepsilon and komega models in CFX/12.1.
However, there is significant difference in velocity predicted by both the models.
k-epsilon model's prediction seems to be incorrect as the boundary layer development seems incorrect as compared to komega model.

Please refer attached velocity magnitude plots and velocity vectors for both the models.In the figures, fluid inlets from the left side at a Re of around 600. Velocity magnitude plots also show the mesh used. I have used a fine uniform mesh. However, I have not ensured any particular y+ at the wall due to use of scalable wall function for k-epsilon model and automatic wall treatment for k-omega model.

Any idea why kepsilon model prediction is so different and seemingly incorrect?

Although inlet Re<1000 calls for use of laminar model as per CFX manual, laminar model does not converge for this case (a possible reason being that the water flows ahead into a porous medium where Re based on pore size is >1 and thus inertia is important in that part of the computational domain which the laminar model is not able to handle).

Thanks for your inputs!