Absorbing Layers for Wave Propagation in Unbounded Medium Using the Subdomain Coupling Method and Hybrid Time Integration

This chapter delves into the numerical simulation of wave propagation in infinite media using the finite element method, focusing on the challenges and solutions related to dissipative boundary conditions. It introduces various artificial boundaries, including absorbing boundary conditions and Perfectly Matched Layers (PMLs), and discusses their implementation in finite element codes. The text highlights the advantages of Absorbing Layers using Increasing Damping (ALID) and introduces Kosloff damping as an alternative to Rayleigh damping. It provides a detailed comparison of the two damping methods, emphasizing the frequency independence of Kosloff damping and its impact on computation time. The chapter also explores the multi-layer design strategy for Kosloff absorbing layers and discusses the coupling method between different domains using hybrid time integration schemes. Numerical applications, including Lamb’s test, are conducted to evaluate the performance of the two absorbing strategies, demonstrating the efficiency of Kosloff absorbing layers in reducing spurious reflected waves and computation time.