A generalised flow prediction method for the unsteady flow generated by a train in a single-track tunnel☆

Abstract This paper presents a generalised one-dimensional flow prediction method for calculating the flow generated by a train in a single-track tunnel. The method is capable of modelling the effects of friction, gradual area change, heat transfer, locomotive heat release, vehicle leakage, and gravity body forces. The underlying theory is based on the method of characteristics and is built into a computer program which allows the above effects to be modelled individually or simultaneously. The characteristic equations are presented and boundary conditions are briefly discussed. An experiment, performed in a full-size rail tunnel, for providing validation data is described. The theory is shown to reproduce the measured transient pressures, temperatures and velocities extremely well. Finally the utility of the method as a design tool is demonstrated for tunnel flow cases involving an entrance flare, coach leakage, locomotive heat release and a gradient. The relevance of each application is discussed.