[Lukas7117]

Hi, I’m trying to conduct 3d transient analysis of natural convection. However using k-w SST model I receive messeage that turb. Viscosity ratio is limited. Such thing happens only when I use water as a fluid, for air it’s ok.

After first time step 0.1 (during internal 30-40 iteration) the problem dissapear and residuals are converging. I change the limit to 10^7 for tueb. viscosity ratio.



My computational domain dimension are 80 mm x 100 mm x 150 mm (height). Side walls are adiabatic, heated wall is at the bottom and the top wall is cooled.



I tried diffrent types of mesh, finer, coarse, polyhedra, hexcore. It doesn't help at all.



I'm wondering if I made some mistake during specification of boundary conditions or if my mesh is really inappropriate.