[HHK]

Hi everyone,
Does anybody know how to maintain the wall y+ value within a range..?

[LuckyTran]

Originally Posted by HHK

Hi everyone,
Does anybody know how to maintain the wall y+ value within a range..?

Remesh? Use smaller cell sizes?

[HHK]

Thank you very much for your reply....I calculated the thickness of near wall prism layer and put prism layer thickness as the turbulent boundary layer thickness.Are these values enough to get the wall Y+ value I need..?..(I didn't get it actually)

[Fresh]

Originally Posted by HHK

Thank you very much for your reply....I calculated the thickness of near wall prism layer and put prism layer thickness as the turbulent boundary layer thickness.Are these values enough to get the wall Y+ value I need..?..(I didn't get it actually)

From my understanding, y+ is very similar to Reynolds number(y*u_t/ν). The idea of maintaining y+ in a range is to ensure that the first layer grid will be located in certain layer(either viscous sublayer, log-law layer, outer layer, etc), for example, viscous sublayer has a y+ <=5(which is non-dimensional) , you could calculate its real thickness if you know u_t and viscosity, that is usually the thickness you want to know, rather than the overall thickness of the turbulent boundary layer thickness which is much bigger than viscous sublayer thickness. This is because certain turbulence models need to resolve such layers, so you have to make sure you have enough data points(prism layers) in that region... Depending on the layer your turbulence model needs to resolve, you choose the prism layer thickness for it.. Does that make sense?