On the Use of Acoustic Analogy and Scale-Resolving Turbulent Flow Computations for Noise Sources Identification

This paper presents aerodynamic noise source identification capabilities for wall-bounded turbulent flows. The employed aeroacoustic methodology is based on the usage of a volume/surface acoustic analogy formulation in the frequency domain, with a tailored Green's function computed numerically. The flow solution and the tailored Green's function used in the acoustic analogy are both obtained from transient and compressible Lattice-Boltzmann CFD simulations using the flow solver SIMULIA PowerFLOW®. In particular, the Green's function is computed by considering the propagation of waves from elementary sources in a quiescent fluid and exploiting the acoustic reciprocity theorem. The methodology is first validated for the case of two vortex-rings in leapfrogging motion in an unconfined environment, by comparing Lattice-Boltzmann direct noise calculations against volumetric acoustic analogy predictions. Then, it is applied to a simplified HVAC system, with and without flap, as well as to a realistic automotive HVAC with a blower, outlining its relevance for the identification of wall-bounded flow noise sources in the context of compressible scale-resolving CFD simulations.