2.Launcher for a train model of an actual shape

Micro pressure wave generated by a train entering a tunnel depends on the shape of the train’s nose and of the tunnel portal. Countermeasures against micro pressure wave therefore involve optimising train nose and tunnel entrance hood design. The train model launcher is used to investigate micro-pressure wave and pressure variation in tunnels. A simple axisymmetric model has been used in the model tests, but, in order to improve prediction accuracy, the launcher capable of projecting more complex train model of an actual shape was developed. The launcher has the same launching structure as existing launcher and the train model of an actual shape was pushed by the former axisymmetric train model (Fig.1). Using by the train model of an actual shape, the pressure on the tunnel wall (Fig.2) and the pressure gradient of the compression wave (Fig.3) which is in proportion to the micro-pressure wave can be simulated more accurate than by the former axisymmetric train model.

The launcher can also be used for experiments investigating aerodynamic phenomena in an open area, such as train draft and low frequency noise.