The Development And Application Of Drainage Model Using Parallel Computing Technique

There has been an increasing interest for last decade to develop numerical models of South-to-North water tranfer project(SNWT).For numerical simulation is a widely adopted technique for decision support, large mount of models referring to different study areas were built. Drainage of SNWT main line occurs when any operation accident happened, so the study of its laws in large scale pipe is of immence importance. Computational fluid dynamics(CFD) models are able to give such insight, because pipe drainage of south-to-north water transfer project is considered to be hydrodynamic process. With simulation results, measures are proposed to deal with low drainage effiency problem. The major research results are presented as follow:(1) SWMM Extran is one of the most common pipe flow models used in simulation of free surface and pressurized flows in closed pipeline and open channel. Flow regulators within the conveyance system can also be controlled dynamically through user-defined Control Rules which is essential for drainage modelling.(2) The main problem of the CFD models is the high computational cost required to accurately compute several scenarios. In order to circumvent this limitation, the general scope of the thesis is to develop a numerical strategy to modify SWMM5.0employing MPI parallel computing technique in multi-processor computers or in distributed enironment. As water movement processes are usually temporally successive, spatial domain decomposition is usually adopted for parallel computing. Based on pipe network sorting algorithm, a practical and dynamic spatial domain decomposition method is proposed. After that, the formula to estimate the speedup ratio is concluded. The framework is tested in Bejing North-to-South water tranfer project(BJNSWT), where48hours of routing process was simulated. Results demonstrate that the system may provide efficient computing performance(3) A friendly manipulating interface was developed for the purpose of wide and long term use of this model. By integrating MPI-swmm as compute engine and SQL server as database, a simulation system is developed. It provides users with multifunctional modeling interface and visualized outputs.(4) To ensure the safty of the water supply and the repairment of main line structures of BJNSWT, drainage model must be set up. An increasing amount of design documents has been collected.These data can be used to produce input of SWMM with a Fortran developed tool. There comes difficulties to model drain structures. We clarify the drainage process into two kinds, free drainage and pumping drainge, depending on whether pump is used. Applying swmm control rules to conceptulized drain structure, two kinds of drainage can swich automatically.(5) To realize drainage operation of BJNSWT, four working condition refering to different working status of drain structures were simulated.Results demonstrate that drain structures manifest different performance on main line drainage. Some drain structures are not as available as they look like. There exist several water body that cannot be drained in any case. Based on the simulation results, measures for raising efficiency of drainage work are proposed and drain structures are characterized in terms of two quantitative indexes.The research is tentative.The model and methods are not used in previous study, further study is urgently needed to testify the conclusions.