Numerical investigation on an array of Helmholtz resonators for the reduction of micro-pressure waves in modern and future high-speed rail tunnel systems

• Published in: Journal of sound and vibration Vol. 400; pp. 606 - 625
• Main Authors: Tebbutt, J.A., Vahdati, M., Carolan, D., Dear, J.P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 21.07.2017; Elsevier Science Ltd
• Subjects: Acoustics; Arrays; Background noise; Design optimization; Elastic waves; Genetic algorithms; Geometric constraints; Helmholtz equations; Helmholtz resonators; High speed rail; Mathematical models; Micro-pressure waves; Multiple objective analysis; Non-linear acoustics; Nonlinear systems; Optimization; Railway tunnels; Shock waves; Shock-capturing schemes; Sound propagation; Sound waves; Train-tunnel aero-acoustics; Tunnels; Vibration analysis; Wave propagation; Micro-pressure waves; Non-linear acoustics; Shock-capturing schemes; Train-tunnel aero-acoustics; Optimization
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2017.04.022

Previous research has proposed that an array of Helmholtz resonators may be an effective method for suppressing the propagation of pressure and sound waves, generated by a high-speed train entering and moving in a tunnel. The array can be used to counteract environmental noise from tunnel portals and also the emergence of a shock wave in the tunnel. The implementation of an array of Helmholtz resonators in current and future high-speed train-tunnel systems is studied. Wave propagation in the tunnel is modelled using a quasi-one-dimensional formulation, accounting for non-linear effects, wall friction and the diffusivity of sound. A multi-objective genetic algorithm is then used to optimise the design of the array, subject to the geometric constraints of a demonstrative tunnel system and the incident wavefront in order to attenuate the propagation of pressure waves. It is shown that an array of Helmholtz resonators can be an effective countermeasure for various tunnel lengths. In addition, the array can be designed to function effectively over a wide operating envelope, ensuring it will still function effectively as train speeds increase into the future.