Okay on my simulation I’ve been using the default boundary layer inflation values with relative sizing. This is achieving y+ values that are a bit high for me to feel confident in them. I have followed the master class tutorial comparing results with/without proper boundary layer configuration, so I understand the importance. Though the tail section is the area of most interest, I need flow to be realistically developed when it hits them.
So I’ve begun trying to refine the boundary layer. I’m using all faces in my boundary layer expansion. Initially I turn off the relative layer sizing with this toggle.
Then I used the y+ calculator with default values for density and viscosity, U=31m/s. I’ve tried a variety of reference lengths, from chord length of the wing to the entire aircraft (~1m - 12m) and a variety of y+ (from 1 - 300) and have built the recommended excel calculator to back-calculate final layer thickness. For purposes of this request, here are two extremes:
|Desired first layer thickness||0.00001199|
|Desired first layer thickness||0.00286|
In both cases, the layers are quite thin. When I then plug the appropriate values into the boundary layer inflation refinement, I inevitably get a failure in the mesh validity checks. Initially the layers look good:
But after refinement they are completely butchered:
If I revert back to relative sizing and the defaults values for the boundary layer inflation, it all passes successfully.
Project is here. The simulation I’ve been using for BL refinement is “510G Deflected”.
While I wait I’m going to remove the feature refinement and attempt a remesh.