Bug unsteady force
@@ -1070,7 +1070,7 @@ def dfunstdgamma_dot(Surfs):
# get (m,n) indices of panel
mm,nn=np.unravel_index( pp, (M,N) )
- dfcoll=Surf.rho*Surf.areas[mm,nn]*Surf.normals[:,mm,nn]
+ dfcoll=-Surf.rho*Surf.areas[mm,nn]*Surf.normals[:,mm,nn]
for vv,dm,dn in zip(svec,dmver,dnver):
