wall y-plus problem: unable to manage between 30 to 300..kindly help..
 

i am pasting the problem link here, below,,, images also attached here...


http://www.cfd-online.com/Forums/mai...-building.html

What turbulence model do you plan to use?
Are you going to use FLUENT (or CFX) for you analysis?

If so, Menter suggests to follow a y+=1 strategy and use a y+_insensitive turbulence model. I think that most of their models are like that now but take that with a pinch of salt as I'm not absolutely sure.

thanx for response....i am using fluent software...and solver is std k-epsilon..with std wall functions (not enhanced)...actually the problem starts when i once run problem....my values of pressure coeff. remain good but y plus falls below 30...as i alter the mesh of those places showing y plus less than 30, it starts showing absurd values of pressure coeff. ,,,so when i control the y plus, pressure coeff becomes absurd...this is the problem.....so i need help.....

Maybe your mesh is too coarse generally. If the mesh was good enough then you would get the Cp right and you wouldn't have the correct Cd. I would try to refine the mesh and go for y+=1 and use enhanced wall treatment.

actually when i refine the mesh to get values of y+=1, gambit crashes with the error: out of memory..so i cant take that much fine mesh..if you can suggest me anything for this ..please..

I don't know if there's going to make much difference but try y+<5 and enhanced wall treatment in Fluent. If you gambit crashes again, go again for y+>30 and standard wall functions.

However, I believe that you should refine your grid generally, not just near the walls.

my ske and rng values are showing much difference ...anyone can point out the reason...