Simulation of exterior noise propagation for the acoustic load estimation of airborne model

Zusammenfassung

The time to market in the automotive industry is constantly decreasing pushing the carmaker companies to increase the efforts in numerical simulations and to decrease the number of prototypes. In the NVH field, the airborne models are widely used for many purposes: from the estimation of the Transmission loss of different parts to the assessment of interior noise due to very complex exterior loads, like aeroacoustic sources. In most cases, the estimation of the exterior load for SEA model is quite complicated and takes a long time to be completed.

The aim of this paper is to present a methodology which is able to forecast the acoustic loads on the exterior surface by exploiting the numerical potentiality of the Fast Multipole Boundary Element Method (FMBEM). In addition, the paper shows a tool that is able to close the gap between the two different methods (FMBEM and SEA), by collecting and processing the data deriving from the FMBEM to be applied to the different panels, which are defined in the SEA method. This is done by a proper averaging – both spatially and in the frequency range – of the pressure for the different panels. The approach is therefore validated by means of a numerical experimental comparison at two different levels: the first one is on the wetted surface, where FMBEM and experimental measurements are compared, while the second one is at the interior cavity level, where the noise level predicted by experimental acoustic loads is compared with the level derived by numerically estimated sources