Mark Carpenter
Computational Methods and Simulation Branch (CMSB)
NASA Langley Research Center
Hampton, Virginia
USA
Temporal simulations of multiphysical systems are frequently characterized by a broad spectrum of time scales, making integration with some form of implicitness mandatory (RK, BDF, GLM, etc). Combination Implicit-Explicit (IMEX) integrators are an alternative approach that can achieve significant efficiency improvements, if the system has separable properties.
A class of the 4th-order, IMEX Runge-Kutta integrators is developed, and applied to applications involving the equations of fluid mechanics. Representative examples that demonstrate different partitioning strategies are presented, including simulations of 1) compressible flow (Discontinuous Galerkin FEM), 2) chemically reacting flows (High-order FD), and 3) Fluid-Structure interactions.