Abstract
An unvented tunnel entrance hood whose effect is equivalent to a vented tunnel entrance hood with open windows distributed along its length is proposed. The vented hood is a principal countermeasure for reducing the micro-pressure wave, and it can reduce effectively the micro-pressure wave by the suitable distribution of its open windows. Because the optimized windows distribution depends on the train nose shape and the train speed, it is necessary to readjust the distribution when the train speed increases or the new type train put into operation. Here, the influence of the cross-sectional area of hood on the effect of reducing the micro-pressure wave is investigated, and the suitable cross-sectional area of the unvented hood, which does not need to be readjusted and its effect is equivalent to the conventionalvented hood with windows, is estimated by the analytical calculation and the model experiments.
