Comparison of High-Order Implicit Time Marching Schemes for Unsteady Flow Calculations

摘要

In many realistic unsteady calculations, the computational grid spacing required to resolve the mean flow gradients is much smaller than the grid spacing required to resolve the unsteady propagating waves. Because of this, the high temporal resolution provided by existing explicit optimized time marching schemes used in computational aeroacoustics code can be excessive due to the small time step required for stability in regions of clustered grid. In this work, optimized and high-order A-stable and L-stable implicit time marching schemes were analyzed, implemented into the AFRL high-order Large Eddy Simulation code FDL3DI, and their performance compared to that of the first and second order implicit schemes currently implemented.