When to use Laminar or Turbulent formulation?
 

Hello,

I want to model Fluid+Heat flow in the air gap between two concentric cylinders. The problem is steady state but I can change the speed of rotation of the inner cylinder.

How do I select between Laminar or Turbulent flow?:confused:

Do I have to calculate the Taylor or Reynolds Nu before:confused:

Will the K-e model predict both:confused:

Thanks!

You may try to see if your Renolds Number falls within the range that the laminar flow may be applicable.

Thanks,

I actually thought of that, but I am doing a parametric study. So for low rpm's I could use laminar and for higher turbulent. However, it doesn't seem right to compare the results from two different models. Any ideas?

hi there

to get a situation of laminar current is pretty tough. theoretically the Re number below 50000 can be laminar current but as a matter of fact we can't get it until 2000. turbulence can be suitable under most of the circumstances unless you want to creat a laminar current situation on purpose. and the standard/RNG/Realizable k-e model is not suitable for the laminar current with a low velocity.

regards