thanks a lot. I will try penalize non-acute triangles.
I’m a beginner in finite elements. The term Laplace(U) transferes to integration of normal derivative of U by the triangle curve. I use Dirichlet Cell as a poligon of circlepoints(of the inscribed circle) of triangles around. If triangulation consists of non-acute triangles, the poligon is not convex and i dont know how what to do with it. May be some other algorithms for calculating Laplace(U) on triangels.