Flow over ribleted surface
 

Hi everyone,

I am currently trying to simulate a turbulent flow over a ribleted plate to see the reduction in wall shear stress(skin friction drag). In order to get accurate results or at least results that show the difference between flat and ribleted surfaces I need to use the viscous sub layer functions.

I am facing the following problems:

1) I understood how to find the distance from the first node to the wall aiming for a y+<1 but I didn´t get how am I suppose to set that on ansys software. Does it have anything to do with the element size??

2) I am working on a average PC that has got ansys student version which only allows me to have 512000 meshing elements. what would be the best geometry and techniche to approach such problem keeping good comparable results and a relatively fast running calculations

3) Also, I read that the values of y+ vary along the surface,Why? If I set y+<1 what else should I do to get accurate values for skin drag??

If you have any other idea or software where I can simulate the same just let me know. :)

Thank you very much,