y+ and wall distance
 

Hi I'm simulating 2D aifoil with salome 7.8

I wanna wall distance. I made mesh with salome, and on FOAM got y+

my goal is 20<y+<30

on FOAM function (simplefoam -postprocess -func yPlus), I could got min :~ max : ~ average : ~

then, average : ~ is y+?? I don't know what is y+(min or max or average)

and at (http://www.pointwise.com/yplus/) there is wall distance (delta s), its mean is grid size in viscous layer??

Thanks

Hi there,

The y+ value will vary over your airfoil between the min and max values you got from the post-processing. If you want 20<y+<30 everywhere (is this the case?) then you need to adjust your grid so that y+_min and y+_max both fall within this range.

The calculator you shared a link to computes the grid size, delta s, along the wall that you need to achieve the specified y+. So plug in y+=20 and y+=30 on the left and it will tell you what grid size to use.