An admissibility and asymptotic preserving scheme for systems of conservation laws with source term on 2D unstructured meshes with high-order MOOD reconstruction

The aim of this work is to design an explicit finite volume scheme with high-order MOOD reconstruction for specific systems of conservation laws with stiff source terms which degenerate into diffusion equations. We propose a general framework to design an asymptotic preserving scheme that is stable and consistent under a classical hyperbolic CFL condition in both hyperbolic and diffusive regimes for any 2D unstructured mesh. Moreover, the developed scheme also preserves the set of admissible states, which is mandatory to conserve physical solutions in stiff configurations. This construction is achieved by using a non-linear scheme as a target scheme for the limit diffusion equation, which gives the form of the global scheme for the full system. The high-order polynomial reconstructions allow to improve the accuracy of the scheme without getting a full high-order scheme. Numerical results are provided to validate the scheme in every regime.