Abstract
Due to the recent strengthening of noise regulations, vehicles with internal combustion engines are required to reduce exhaust noise. To improve development efficiency, we have been required to develop a technology that quantitatively predicts the pulsating noise caused by engine combustion and the airflow noise caused by exhaust gas flow, which constitute exhaust noise. Especially, the frequency characteristics of airflow noise could not be predicted before. This report describes the development of a technique for quantitatively predicting the frequency characteristics of exhaust airflow noise using a hybrid method that combines CFD (Computational Fluid Dynamics) and acoustic analysis.
