About plot the y+ and u+ in CFD
 

Hi

I'm simulating the flow in a tube with steady simulation according to the setting in an PIV experiment. I plot the y+ and u+ profile as follows, and the difference is significant in log region. The number and thickness of the prism layer are adjusted, but the results are still unsatisfactory.

The valuses of the friction velocity obtained are also smaller than the experiment based on the Prandtl’s friction law.

Anyone could give me some advice about how to improve the results? Thank you in advance.