Relation between Exhaust Pulsating Flow and Radiation Noise: On methods of analysis of the generation mechanisms of radiation noise in exhaust pulsation and some observations

摘要

The purpose of this study is to clarify the relation between exhaust pulsating flow and radiation noise. This paper first describes how to measure exhaust pulsation with accracy. By applying the measured values to boundary conditions of the model, accurate radiation noise from the exhaust system is obtained, and the noise causing parts and the mechanism are clarified. Also, this newly developed method predicts the radiation noise in a sound field located away from the vibrating surface of the structure by coupling calculation between fluid exhaust gas and exhaust parts. The method enables the investigation of exhaust radiation noise in an early development stage.