Hierarchical Hybrid Grids for Mantle Convection: A First Study

In this article we consider the application of the Hierarchical Hybrid Grid Framework (HHG) to the geodynamical problem of simulating mantle convection. We describe the generation of a refined icosahedral grid and a further subdivision of the resulting prisms into tetrahedral elements. Based on this mesh, we present performance results for HHG and compare these to the also Finite Element program TERRA, which is a well-known code for mantle convection using a matrix-free representation of the stiffness matrix. In our analysis we consider the most time consuming part of TERRA's solution algorithm and evaluate it in a strong scaling setup. Finally we present strong and weak scaling results for HHG to verify its parallel concepts, algorithms and grid flexibility on Jugene.