AERODYNAMIC NOISE: A CRITICAL SURVEY

Annoyance due to railway noise is a particularly sensitive aspect of new high-speed projects. Many studies have shown that aerodynamic noise becomes significant above 300 km/h and can become predominant with the reduction of the contribution of rolling noise. At the moment, no further global reduction of high-speed train noise can be achieved if the aerodynamic noise is not reduced. The objective of this paper is to provide a critical survey of the aeroacoustic noise problem for trains, particularly for high-speed trains. The first step in any acoustic study is to identify the different sources. This paper describes the different aeroacoustic phenomena which are representative of high-speed trains and the technical methodologies used to characterize these phenomena. Specific tools have been developed from on-line tests, wind tunnel experiments, theoretical studies or numerical simulations to characterize the different sources. Using examples, the limitations of the methods and the solutions currently available are reveiwed today. Methods of global modelling of a high-speed train emission are also presented. Finally, future development of new tools based on numerical simulation in aeroacoustics are discussed.