Analytical Prediction of Reflection Coefficients for Wave Absorbing Layers in Flow Simulations of Regular Free-Surface Waves

摘要

Undesired wave reflections, which occur at domain boundaries in flowsimulations with free-surface waves, can be minimized by applying source termsin the vicinity of the boundary to damp the waves. Examples of such approachesare absorbing layers, damping zones, forcing zones, relaxation zones and spongelayers. A problem with these approaches is that the effectivity of the wavedamping depends on the parameters in the source term functions, which arecase-dependent and must be adjusted to the wave. The present paper presents atheory which analytically predicts the reflection coefficients and which can beused to optimally select the source term parameters before running thesimulation. The theory is given in a general form so that it is applicable tomany existing implementations. It is validated against results fromfinite-volume-based flow simulations of regular free-surface waves and found tobe of satisfactory accuracy for practical purposes.