Hi I want simulation turbulence flow in long tube. my Re number 10000~20000 There are two way to simulation Wall-Bounded Turbulence. 1.wall function 2.two-layer zonal model For two-layer zonal model,it is good for low Re number What is low Re number ?

(1). Before you start any flow simulation, it is a good idea to take a look at the book by David. C. Wilcox,"Turbulence Modeling for CFD". It's available from the author's website and can be found in the cfd/forum/resources. (2). You should be able to find the answer of "low Reynolds number model" in Wilcox's book.