Prediction and validation on the sonic boom by a high-speed train enteringa 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. T here are various countermeasures to reduce the micro-pressure wave, the mos t 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. Th e Euler equation is first solved. after which the linear Kirchhoff formulat ion is used for the prediction of farfield acoustics from the flow-field da ta. Experimental investigation is also carried out on the pressure fluctuations in the tunnel and the micro-pressure wave with parameters such as train sp eed, 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 countermeas ures could be used for the efficient reduction of the micro-pressure wave. (C) 2001 Academic Press.