PREDICTION AND VALIDATION ON THE SONIC BOOM BY A HIGH-SPEED TRAIN ENTERING A TUNNEL

A compression wave generated when a high-speed train emerges from the exit portal of a tunnel, causes an impulsive noise called micro-pressure wave. There are various countermeasures to reduce the micro-pressure wave, the most effective one being the proper design of the nose shape of the train. In the present study, we adopted a new method for the prediction of sonic boom noise, considering the effect of the nose shape on the resultant noise. The Euler equation is first solved, after which the linear Kirchhoff formulation is used for the prediction of farfield acoustics from the flow-field data. mental investigation is also carried out on the pressure fluctuations in the tunnel and the micro-pressure wave with parameters such as train speed, blockage ratio, nose shape of train and air-shafts. The computational prediction and experimentally measured data, compared in this paper, show a good agreement with each other. The results shows that several countermeasures could be used for the efficient reduction of the micro-pressure wave.