y+ in high Pr flows
 

Does anyone have experience with computing heat transfer in oil (or other high Pr fluid) flows? What is the ideal, near wall spacing to use for high Pr flows?

I'm interested in computing the Nu for both laminar as well as turbulent flow regimes in some tube cross-sections carrying oil and the Pr of the flows. I am looking at Pr in the range of 100 - 150.

While I am able to accurately get the pressure distribution correctly, my Nu distribution is not correct, which of course is due to the thinner thermal BL. My mesh is already pretty resolved and my y+ is of the order of 0.1. Should it be lower/higher? This is my first experience with high Pr flows.

I guess there should be a similar phenomena someone might have come across in mass transfer too.