K epsilon Model
 

Hello,

i am working on a small projekt with star ccm+. I am using a k Epsilon model for turbulence. Ist used to estimate the reynolds stresses for high reynolds numbers. But i think there is a second one, for low reynolds numbers.

Can anyone explain me the difference between this two equations?

Standard k Epsilon model and low reynolds number model.

thank you

The difference in the two models comes in how they treat the near wall flow. The low Re model is supposed to be used with a mesh that has a y+ value = 1. This low re model is resolving the flow all the way to the wall. The standard model is to be used with a mesh that has a y+ value of 30-300 it uses wall functions to resolve the flow near the wall. These two models can be used to model the same flow the "low Re" model does not mean its used for only low reynolds number flows, it is talking about the laminar flow near the wall. If you can search about what y+, wall functions, and boundary layer you will easily understand the difference between these two models.

thank you for your answer, it helps me