Year: 2018 Volume: 1 Issue: 3 Page: 168-174
LARGE EDDY SIMULATION AND AEROACOUSTIC ANALYSIS FOR SIMPLE EXPANSION SILENCER LIKE GEOMETRIES
This study includes compressible large eddy simulations performed for flow predictions inside circular pipes resembling automobile exhaust pipes. Compressible large eddy simulation approach is selected because of its ability to resolve complex turbulent flow fields along with the wave motions present. Three geometries including the pipe alone and the pipes which include simple expansion chambers with circular and elliptical cross-sections are studied. The acoustic performances of the geometries are analyzed by recording the pressure fluctuations at the exit of the pipes. Predictions showed that the presence of a simple expansion chamber can reduce the pressure fluctuations not only by the expansion they provide but also by the wave reflections from the open ends and solid surfaces.Power spectral densities of the pressure fluctuations at the exitsof the pipes showed that the noise improvements by the expansion chambers are more evident at lower frequencies which become more pronounced when an A-weighting procedure was applied.
Anahtar Kelimeler (Keywords): Engine Exhaust Noise, Simple Expansion Silencer, Compressible Large Eddy Simulation, OpenFOAM, Aeroacoustics