[nmartin9319]

Hi!

I have to calculate the flow field in a stirred vessel (15 mm radius, 15 mm height) where the blades (10 mm radius) at the top of the geometry rotating with 3000 RPM.

It's a transient simulation, and until now I've tried to solve it with SST, since the Reynolds number is around 150000. The convergence is good, but if I want to keep the abs RMS at 1e-5 in every variable, then I have to run it with small stepsize (~1e-6 s) for about 5 seconds. Unfortunately I don't have that much time.

First it seemed like an idiotic idea, but I've tried to solve it without any turbulence modelling, and it worked. With 1e-3 s stepsize, the abs RMS in the velocities decresed to 1e-6 and to 1e-4 in the continuity in 10-20 iterations. The results also seem valid.

My question is that why the laminar model working in an obviously turbulent case. My mesh consists ~500k elements, so I doubt that I'm in the DNS regime. Should I believe my results? (I'd love to, but not sure)

Thanks in advance