Aero-acoustic simulation of a side mirror compared with experimental results

摘要

The study of aero-acoustic noise generated by a fluid in motion is critical for the transportationrnindustry. New designs must respect stringent criteria to reduce environmental and passenger noise. Thernavailability of a mature computational aero-acoustic (CAA) technique is essential to achieve this goal.rnWind noise problems, for instance, require a good representation of the turbulent noise generation andrnan accurate propagation of the noise through the fluid in motion.rnA side mirror noise simulation is presented here. The time domain fluctuations of the pressure andrnvelocity fields are directly computed using a finite element (FE) transient solution of the 3Drncompressible Navier-Stokes equations. Key features of the solver include explicit time integration, arnStreamline-Upwind-Petrov-Galerkin (SUPG) non-diffusive scheme, a sub-grid-scale model for thernturbulent structures (Large Eddy Simulation), and effective silent boundaries. The simulation was runrnon a Cray SX-6 parallel-vector-supercomputer.rnWe compare the FE model (700,000 elements) of a simplified side mirror to experimental results. Thernhighly unsteady turbulent wake is analyzed both in terms of average flow and fluctuations. The pseudoacousticrnnoise spectra at various locations display a good agreement between experiment andrnsimulation.rnThis work opens the way to other external aero-acoustic problems.