Guidance on building models with vertical tails

[Cindy Chen]

Hi all,

I am running a VSPAero analysis on a BWB with two vertical fins near the trailing edge of the centerbody (at y = +/- 1.9). I modelled the BWB and fins as separate WingGeoms. The fin roots barely intersect the BWB. When I run a VLM stability analysis, the resulting local lift distribution looks like the attached, with a  peak at y = 1.9. What's odd is that even though the fins are symmetric about the centerline, the peak is only on one side. 

The peak arises due to a singularity in the VLM solution at the fin-BWB intersection. I tried coarsening and refining the chordwise and spanwise panel resolutions on the fins and ensured that the fin camber surface does not coincide with any panel boundaries, but the peak remains. Does anyone have any ideas on how to fix this, or general guidance on building models with vertical tails? My model is attached if you would like to take a look.

Thanks,

Cindy