Analysis on setting airshaft at mid-tunnel to reduce transient pressure variation

Setting airshaft is one of the methods efficient to control the aerodynamic effects on a train traveling through a tunnel. By using numeral simulation, analysis is carried out on the effect of airshaft on transient pressures generated in cabin. After setting airshaft, the magnitude of pressure fluctuation in cabin is reduced nearly 40%. By analyzing the role of airshaft in alleviating pressure fluctuation, a formula to determine the optimal airshaft position is deduced.