Is there a way to find a correct "spacing"?
 

Hello!

I'm meshing a cross flow heat exchanger and I don't know how to define the correct spacing near the wall. Is there some formula to find this correct spacing?. When I say "correct" I mean the wall Yplus be less than 1.

Jordi

you can calculate the boundary layer first row height regarding to the flow condition you have with this program that NASA provides:

http://geolab.larc.nasa.gov/APPS/YPlus/

Well!
 

Thanks very much! the program works well, but in my case (turbulent flow passing around some cilinders) after calculating with it I've had to do 1 Wall Yplus adapt, but after doing this, Y+ is less than 1. Bye!

Jordi P.