Numerical prediction of sound emission of confined flows based on a hybrid approach

The absence of combustion noise in electric vehicles results in a dominance of other sources of sound, such as flow-induced sound in flow guiding components. The use of computational aeroacoustics (CAA) during the design phase is a promising way to fulfill the packaging requirements as well as the ambitious demand for passenger comfort. By coupling the computational fluid domain with the surrounding structural domain via coupling conditions on the interface, not only the sound generation and propagation within the fluid can be computed, but also the vibroacoustic sound emission of the flow-guiding structure can be simulated. We propose such a numerical model based on a hybrid approach for the prediction of the sound emission of the confined flow. Thereby, different aeroacoustic formulations (Lighthill’s acoustic analogy, vortex sound theory, PCWE) are considered and the results are compared against measurements. First, the aeroacoustic source terms are computed by an incompressible Large-Eddy Simulation of the flow (Ma<0,3) based on the finite-volume method. The propagation of the aeroacoustic sources is then simulated by the in-house finite-element solver openCFS, which allows a coupling of the acoustic and the mechanic fields of the confining structure.