Abstract
An urban storm water runoff phenomenon in which manhole covers in a storm sewer pipe system are blown away has occurred frequently during heavy rain. This phenomenon occurs due to the compression of air in manholes and sewer pipes, and the compression is caused by the rising storm water surface. In this paper, an urban storm water runoff simulation model that can simulate the air movement and temporal and spatial variations of air pressure in the pipe system is presented. At first, basic equations for air flow and storm water flow in the pipe system are derived. Secondly, a numerical simulation method for the basic equations that is a characteristic grid method of specified time intervals is proposed. Finally, the applicability of the simulation model is examined by applying the model to runoff experiments. As a result, it is concluded that the model is a useful and practical simulation model, which can precisely simulate the air movement in the sewer pipe system during a heavy rain.
