A Pipe Network Simulation Model with Dynamic Transition between Free Surface and Pressurized Flow

Water flow numerical simulation in urban sewer systems is a topic that combines surface flows and pressurized flows in steady and transient situations. A numerical simulation model is developed in this work, capable of solving pipe networks mainly unpressur- ized, with isolated peaks of pressurization. For this purpose, a reformulation of the mathematical model through the Preissmann slot method is proposed. The numerical model is based on the first order Roe's scheme, in the frame of finite volume methods. The validation has been done by means of several cases with analytic solutions or empirical laboratory data.