Aeroacoustic sources in turbulent flow through a pipe with a sharp orifice predicted by Large-Eddy Simulation.
* Presenting author
Abstract:
The method of Large-Eddy Simulation (LES) has increasingly gained popularity, as it encompasses the direct resolution of a major part of the vortical motion in a turbulent flow field. The uncertaintyof turbulence modeling is thus limited to the unresolved sub-grid scales (SGS). This makesLES a highly attractive method for predicting flow-induced sound sources for use in Hybrid Computational Aeroacoustics (CAA). The possible sound emission generated by turbulent vortical motion is of growing importance in the design of flow-guiding components. This is especially the case in electric vehicles, where the masking noise of the combustion engine is absent and limited space in the engine compartment of the vehicle may lead to unfavorable flow-conditions.The present study performs incompressible LES to predict the turbulent flow field downstream of an orifice inside a circular pipe. The computational results are compared against experimental data from dedicated measurements. The predicted instantaneous flow field is used to evaluateaeroacoustic source terms for different acoustic equations, such as Lighthill’s acoustic analogy or the Perturbed Convective Wave Equation (PCWE).The contribution of the unresolved scales, which is supplied by the employed SGS-model to the acoustic sources, is specially investigated.