Intrusion Process of Flood Water into Underground Space

This paper deals with the propagation of the interface between the open channel flow with free surface and the pressurized pipe flow, which is related to the flood and storm water intrusion into the underground space such as a sewer network, a subway system and a underground market. The fundamental phenomena are reproduced numerically by using the simulation model developed in the paper. The basic equations are composed of the continuity and momentum equations for both water and air flows under the assumption of incompressible flow. Numerical procedures with the treatment of the propagation of interface are shown in detail and applied for the typical flows which may occur in the underground space. It will be pointed out from the comparison between the calculated and experimental results that it is necessary to take account of the effect of the air pressure in the model.