One-dimensional flow analysis of steady pressure field around a train running in a long tube with a constant width slit

Abstract

A one-dimensional theoretical analysis is made of the pressure field around a train running in a long tube with a constant width slit, which is a simplified model of partially enclosed structures (or vented tubes) of railway, such as snow shelters or whole covered stations. It is shown from field measurement results in Shinkansen that the pressure field produced in such partially enclosed structures exhibits a pattern of ‘a combination of single sawtooth and its reverse’. The present analysis of a tube with a slit reproduces this unique pressure pattern and shows that one-dimensional pressure field ahead of the train nose and tail can be expressed by elementary functions. It also reveals that the magnitude of the pressure change around the tail can exceed that around the nose, which is also a unique feature that is different from the cases of open air spaces and fully enclosed spaces (i.e., tunnels).