Fig. 4
From: Multilevel preconditioners for embedded enriched partition of unity approximations
Sketch of a non-convex domain \(\Omega \) in two dimensions depicting the employed partitioning into \(\Omega _{\mathrm {HOST, FT}}\) (drak gray), \(\Omega _\Phi =\Omega _{\mathrm {HOST}}\cap \Omega _{\mathrm {ENR}}\) (light gray), and \(\Omega _{\mathrm {ENR, FT}}\) (white). The boundary data for this model problem is given by \(g=0\) on \(\Gamma _D\) and \(h=\nabla \Big ((x^2 + xy + y^2 + 1)(r^\frac{2}{3} \sin (\frac{2\theta - \pi }{3}))\Big ) \cdot n\) on \(\Gamma _N\) where n denotes the outer normal