The non‐reflective interface: an innovative forcing technique for computational acoustic hybrid methods

Abstract

SummaryThe present article concerns a commonly used methodology for the numerical simulation of acoustic emission and propagation phenomena. We consider the so‐called multi‐stage hybrid acoustic approach, in which a given noise problem is simulated via a sequence of weakly coupled computations of noise generation and acoustic propagation stages, wherein the simulation of the propagation stage is based on advanced Computational AeroAcoustics (CAA) techniques. The paper introduces an original forcing technique, namely, the Non‐Reflective Interface (NRI), to enable the transfer of an acoustic signal from an a priori noise generation stage into a CAA‐based acoustic propagation phase. Unlike most existing forcing techniques, the NRI is non‐reflective (or anechoic) in nature and, therefore, can properly handle the backscattering effects arising during the noise propagation stage. This attribute makes the NRI‐based weak‐coupling procedure and the associated CAA‐based hybrid approach compatible with a larger variety of realistic noise problems (such as those involving installed configurations in wind tunnel experiments, for instance). The NRI technique is first validated via several test cases of increasing complexity and is then applied to two aerodynamic noise problems. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.