Far-field filtering operators for suppression of reflections from artificial boundaries
SIAM Journal on Numerical Analysis
A super-grid-scale model for simulating compressible flow on unbounded domains
Journal of Computational Physics
Analysis of sponge zones for computational fluid mechanics
Journal of Computational Physics
Journal of Computational Physics
A high-order super-grid-scale absorbing layer and its application to linear hyperbolic systems
Journal of Computational Physics
An adaptive implicit-explicit scheme for the DNS and LES of compressible flows on unstructured grids
Journal of Computational Physics
Hi-index | 31.45 |
The aim of this work is to provide practical guidelines for designing sponge layers considering applications in computational fluid dynamics and computational aeroacoustics. We present the analysis of sponge/flow interactions and provide a characterization of its basic reflectivity mechanisms. While sponges are perfect absorbers in one-dimensional systems, they can cause their own reflection when encountering oblique sound or oblique vorticity waves. To minimize this adverse effect, sponge strength and profile need to be selected optimally. Also for a fixed desired accuracy, sponge length should be above a minimum threshold. Our analysis quantifies these requirements for a wide range of conditions in terms of inflow/outflow Mach number, incident frequencies, incident angles, and desired accuracy, and covers main concerns with sponges such as sound/sponge interactions and vortex/sponge interactions. As a test case, we present a nonlinear Euler calculation of a convecting vortex interacting with sponges with different lengths. We show that sponges designed by our guidelines achieve accuracies comparable to perfectly matched layers for the same cost, over moderate to high accuracy demands. The results of the presented analysis can be used to determine sponge requirements for a wide range of CFD applications. A summary of these guidelines are listed in the paper.