Relation Between Exhaust Pulsating Flow and Radiation Noise: Development of Exhaust Radiation Noise Simulation Technology

The purpose of this paper is to clarify mechanism of the relation between exhaust pulsating flow and radiation noise,and developing simulation technology based on the fact of these phenomena. The simulation takes into account fluid flow pulsation,aero-acoustic noise sources, flow induced structural vibration as well as noise radiation in the far field. All those phenomena are directly calculated in a fully coupled manner. By applying measured values at the model inflow, accurate radiation noise from the exhaust system is obtained. Locations of noise sources as well as mechanisms of noise generation are clarified. The method enables the investigation of exhaust noise radiation at early development stages.