Learning Forum

[akndnzmn]

Hello,

 

I want to add wall roughness effect into my analysis, and I have experimental Ra data for my walls. I have done some research on this, but when I combine the things I find, I just get confused. How can I use the Ra values in a fluent or Is it possible to convert Ra data to Ks (Sand Grain Height)?

 

Surface Finish

0.4

0.4

0.4

0.8

[Prashanth]

Hello,

If we are talking about the modified standard law-of-the-wall models, Fluent only uses sand-grain roughness based on Nikuradse's experiments. Fluent does not have any correlation to convert surface finish values to k_s (not all rough surfaces are same). You would mostly need to tune the Fluent sand garin roughness parameters to match with the experiments, and then proceed from there, and take help from published literature.