Traffic noise is the most important environmental noise source in Europe. As many as 25% of the population in Europe is exposed to transportation noise with an equivalent sound level over 65 dB(A). It is a clearly stated goal of the GROWTH work programme to reduce the pass-by noise to 70 dB(A) for automobiles and 74 dB(A) for heavy vehicles. Reduction of the noise from exhaust and inlet systems is essential for reaching the pass-by noise targets.

Improved simulation programmes for predicting the noise generation caused by unsteady flow in exhaust and inlet systems are very important for this purpose as well as for reducing the amount of experimental testing needed to develop a new product. The main objective of the project is to develop the models needed for computational tools to predict sound generation from turbocharged engine exhaust and air inlet systems.