A methodology for the prediction of the sonic boom in tunnels of high-speed trains. (28th April 2019)

• Record Type: Journal Article
• Authors: Rivero, Juan Manuel; González-Martínez, Ezequiel; Rodríguez-Fernández, Manuel
• Is Part Of: Journal of sound and vibration. Volume 446(2019)
• Page Start: 37
• Page End: 56
• Publication Date: 2019-04-28
• Subjects: High-speed train -- Train aerodynamics -- Tunnel aerodynamics -- Sonic boom -- Shock wave -- Method of characteristics; Sound -- Periodicals; Vibration -- Periodicals; Son -- Périodiques; Vibration -- Périodiques; Sound; Vibration; Periodicals; Electronic journals; 620.205
• DOI: 10.1016/j.jsv.2019.01.016
• Languages: English
• ISSNs: 0022-460X

Abstract

Abstract: The present study focuses in the propagation and deformation of the first compression wave generated when a high speed train enters a tunnel. This first wave is a determining factor in shock wave formation inside the tunnel, and therefore in sonic boom phenomena. This is modelled with the one-dimensional equations for the flow in a tube, and an analogy that relates a piston inside a tube with the entering train, both opening the door to an algebraic formulation that delimits the problem of shock formation. The model is represented in a characteristic form to find the relation between the distance where the pressure wave becomes a shock wave (named the regression distance) and the parameters that define the initial wave profile, namely the maximum pressure increment and the maximum pressure gradient downstream the entry portal. Later, steady and unsteady wall friction and heat transfer effects are analysed. Differences between the regression distance for the cases with friction and heat transfer and without them, seems to be delimited, that makes the algebraic formulation suited for fast decisions at the time of conceptual design of high-speed lines. Model validation with more complex models and experimental data is provided. Highlights: Application of the method of characteristics for solving the governing equations. A piston analogy for recreating the entry pressure wave of a highspeed train. Parametric analysis on the distance required for the shock wave formation. Relevance of friction and heat transfer terms that attenuate the pressure wave. Operational chart of tunnels for avoiding shock wave formation.