[Rozpruwacz]

Hello,

I'm just out of college and staring my career in CFD. I have a question regarding natural convection in closed cavities.

How do I determine flow type for my CFD simulation?

I know that we can judge flow type by Reynolds (Re) number in forced convection and Rayleigh (Ra) number, which is a product of Grashof (Gr) and Prandtld (Pr) numbers, in natural convection. However, only critical values of Ra that i've found is 10^9 for vertical plate cooling (found in Y.Cengel "Heat Transfer. A Practical Approach." as well as T.L Bergman et all "Fundamentals of Heat and Mass Transfer") and 10^6 for squared cavity (found here: https://www.researchgate.net/publica...nclosed_cavity).

How do I proceed when my geometry is not one of those two. For example consider "cylinder in cylinder" cavity presented on the picture below: .

I tried to find some resources with similar geometry and H/R ratio but I was not able to find anything. How then can judge character of my flow?

Best Regards,
Wojtek