Hi everyone,

I'm currently simulating incompressible, adiabatic flow through a 2d compressor cascade. I want to use the k-w turbulence model, but I am unsure of the y+ range. As far as I know it uses a wall function and thus I assume that the y+ range should be in the range 30<y+<100. Is this assumption correct? Does the adverse pressure gradient change the range of y+? References would be appreciated, as my results will be included in a technical paper.

It seems that part of my post was cut off. Here's the rest: ...should be in the range 30 to 100. Is this correct? References would be appreciated, as this forms part of a technical paper.

For high Reynolds number cases y+ should be aroound the range you've mentioned so that your first cell is NOT in the laminar sublayer. However, for low Reynolds number cases it should be lower, and in particular whne you are more interested in boundary layer related phenomena y+ should be below 1. For more information, you can have a look at "An introduction to Computational fluid dynamics, The finite volume method" by H K Versteeg & W Malalasekera.

The k-w model of Wilcox was originally not based on wall function or hi-Re formulation as I understood it unlike the kw-SST.

I don't think locating the first node near the wall within y+ of less than 30 or 70 would create a problem for k-w original as it was not based on wall function. However, in Star-CD the k-w seems to have both low-Re and high-Re options and so it is not clear (to me at least). Would appreciate some input.

Visser, refer quickly this link below before reading more texts.

https://pronet.wsatkins.co.uk/marnet...nes/guide.html

Sheila is right. The high-Re k-w uses a wall function, so the y+ range should be between 30 and 100. For low-Re k-w the y+ should be less than 1. A certain number of cells (not sure how many) should be in the boundary layer when using the low-Re k-w.

Hi,

Can you tell me how to plot wall function values in prostar.Also what will happen if the values of y+ goes below 30 in case of high Re k-w model.