Abstract
Hydraulic transients in the underground channel system such as underground flood ways and sewer networks are investigated experimentally and numerically. The typical features of unsteady flows induced by the inflow discharge into the underground channel are clarified by the fundamental hydraulic experiments. It is shown that the hydraulic transients with the propagation of an interface between open channel flows and pipe flows can be reproduced by using the numerical model. The fundamental numerical model is refined to predict the interaction between overland surface flows and underground channel flows, considering the discharge through manholes. The pressure change of air confined in the underground channel is also considered in the model to reproduce the spout of underground flows over the land surface through manholes.
