Numerical Simulation of Sewer Sediments Transport in Drainage Pipe Network Based on Weak Coupling Approach

Abstract:

Sewer network hydraulic and quality simulation with consideration of sediment transport is conducted by coupling with the storm water management model (SWMM)with the sediment transport model (STM). Using this coupling model, the sediment load concentration and hydraulic cross section deformation of conduit caused by sediment transport in the sewer network can be quantitatively calculated. The global time step length of the coupling model is determined by the SWMM, and the STM is modified to adapt to the global time step so that the numerical stability in the simulation process can be achieved, and unsteady cases caused by over deposition and over flushing are avoided. The proposed coupling model was applied to two study cases, whose results show that this coupling model is stable and logical. The sediment flushing and deposition cycle and its impacts on load concentration and hydraulic cross section deformation of conduits can be simulated. Comparisons between simulation results and observed data indicate that the simulation results obtained by the proposed coupling process fit the observed data better than the simulation results without the coupling process.

Key words:sewer system;SWMM ( storm water management model );sediment transport model;numerical simulation