Excessive temp. within boundry layer for roughness 0.0003 to 0.0007m
 

Good afternoon
Trying to simulate roughness (0.0003m to 0.0007m roughness height) in a nozzle and investigate the effect of roughness on mass flow rate but there is a problem. I get excessive temp. here is a screenshot of the contour of static temperature:


https://www.cfd-online.com/Forums/at...1&d=1532349676



As you can see at the throat this excessive temp. has taken place. why? Any idea to figure it out?

Have you tried remeshing?

Thank you for your response
Well no, To have mesh for roughness 0.0007m and fully rough(epsilon plus >70 or k+>80) I think I need to have a mesh with 0.0014m (two times of 0.0007) hight for first cell near the wall. I think my mesh is not that bad. If you think I need to re-mesh this flowfield, please let me know what's your idea to re-mesh it.