CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Default settings for 3D boundary layer-Gambit 2.2 (http://www.cfd-online.com/Forums/fluent/41876-default-settings-3d-boundary-layer-gambit-2-2-a.html)

Ramine July 28, 2006 09:04

Default settings for 3D boundary layer-Gambit 2.2
 
Hi,

I've meshed my 3D wings without a boundary layer in Gambit expecting to refine my grid in Fluent but I'm not happy with what I get and I would like to refine it more precisely without increasing too much my number of cells. This is why I'm going back to Gambit in order to try the boundary layer option.

For my mesh, I've divided the foil in two boxes (one for the tip which I'm studying more particularily and one for the root) plus a big bonding box surrounding the whole thing.

I'm using a curvature size function to create a triangular mesh on the foils and a mesh SF to mesh the volumes.

Since I've tried using the boudary layer tool, I got all sorts of different results and I'm not really sure how to get a mesh right the first time or at least, which settings to change in order to get the BL cells not to be skewed and especially at the hydrofoil's trailing edge where the BL ends with skewed cells.

So far, I've set the ANGLE_SMOOTH_FACTOR and ADJUST_EDGE_BL_HEIGHT to 1 which helped me to get a mesh but with a few highly skewed cells at the trailing edge. I then changed the ORTHOGONAL_LAYER value to 5 in order to try to get a less skewed BL mesh but I'm still not convinced! And the latest is that I'm getting a floating-point exception when I attempt to mesh the volume...

As there are so many settings in the BLAYER or BLAYERTGRID and I'm not willing to try them all as it takes a long time to remesh each time, does anybody knows a "rule of thumb" or some basic defaults settings I need to modify in order to get a correct 3D BL mesh over my hydrofoils?

Sorry for the long text!

Cheers,

Ramine

Ramine July 31, 2006 12:36

Re: Default settings for 3D boundary layer-Gambit
 
I've changed my trailing edge geometry and now I can mesh the foil correctly...

The edge was sharp and now I have a 0.5mm face in order to get rid of the boundary layer skewed cells...

Ramine


All times are GMT -4. The time now is 05:46.