Advanced acoustic simulation of aircraft test environments: integration of the direct field acoustic testing methodology

Abstract

In aeroacoustic engineering, replicating real-world environments in a controlled setting presents significant opportunities for reduced flight testing but also comes with challenges when precisely simulating the flight environment. This paper introduces an innovative acoustic simulation model that leverages the Boundary Element Method (BEM) and a Direct Field Acoustic Testing (DFAT) simulation module. The primary objective is to virtually reproduce test sound fields that closely mimic the full fluctuating pressure environments aircraft encounter during flight using only loudspeaker arrays. This approach involves virtually reproducing a sophisticated test setup, typically comprising hundreds of drivers actively managed to generate a specific sound field. This setup is designed to virtually replicate various complex pressure environments, such as those produced by a Turbulent Boundary Layer, the complex pressure fields generated by aircraft propellers or jet engines. The use of active noise generation simulation helps determine the feasibility of a given pressure field and the capability of a test facility to simulate it accurately. The virtually reproduced sound fields simulated by this model show remarkable potential in approximating real-world pressure loadings. This capability is particularly useful in establishing pre-test predictions for fuselage testing such as sidewall build-ups: including insulation, and damping treatments, TVAs and TMDs.