A massively parallel Eulerian-Lagrangian method for advection-dominated transport in viscous fluids

03/03/2021

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by   Nils Kohl, et al.

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Motivated by challenges in Earth mantle convection, we present a massively parallel implementation of an Eulerian-Lagrangian method for the advection-diffusion equation in the advection-dominated regime. The advection term is treated by a particle-based, characteristics method coupled to a block-structured finite-element framework. Its numerical and computational performance is evaluated in multiple, two- and three-dimensional benchmarks, including curved geometries, discontinuous solutions, pure advection, and it is applied to a coupled non-linear system modeling buoyancy-driven convection in Stokes flow. We demonstrate the parallel performance in a strong and weak scaling experiment, with scalability to up to 147,456 parallel processes, solving for more than 5.2 × 10^10 (52 billion) degrees of freedom per time-step.