Multiscale methods for wave problems in heterogeneous media

TL;DR

This survey reviews multiscale numerical methods for solving second order hyperbolic wave equations in heterogeneous media, addressing both non-scale-separated and scale-separated scenarios with different computational strategies.

Contribution

It provides a comprehensive overview of multiscale approaches tailored for heterogeneous media, highlighting methods for both natural and engineered structures with and without scale separation.

Findings

Generalized finite element methods effectively handle non-scale-separated media.

Homogenization techniques reduce computational costs in scale-separated media.

Different approaches are suited for geosciences and engineering applications.

Abstract

In this paper we give a survey on various multiscale methods for the numerical solution of second order hyperbolic equations in highly heterogeneous media. We concentrate on the wave equation and distinguish between two classes of applications. First we discuss numerical methods for the wave equation in heterogeneous media without scale separation. Such a setting is for instance encountered in the geosciences, where natural structures often exhibit a continuum of different scales, that all need to be resolved numerically to get meaningful approximations. Approaches tailored for these settings typically involve the construction of generalized finite element spaces, where the basis functions incorporate information about the data variations. In the second part of the paper, we discuss numerical methods for the case of structured media with scale separation. This setting is for instance encountered in engineering sciences, where materials are often artificially designed. If this is the case, the structure and the scale separation can be explicitly exploited to compute appropriate homogenized/upscaled wave models that only exhibit a single coarse scale and that can be hence solved at significantly reduced computational costs.