Research On Response Of Unsteady Water Transport And Operation Control In The Middle Route Of The South-to-North Water Diversion Project

The Middle Route of the South-to-North Water Diversion Project (MRSNWD) is a large-scale water conveyance project with long channel, large span, wide range of supplied region and all flow automatically without any reservoir along the channel; therefore the hydrodynamic problem of long-route water conveyance and current transmit and response will be very complicated. Characteristic of unsteady-flow in main channel and stability of water conveyance and the best operation control are key problems to insure the channel transmit water safely and stably.In this paper a one-dimensional numerical model was developed for unsteady-flow in a large-scale conveyance channel with complex inner boundary conditions. Generalized equations describing the complex inner boundary conditions such as regulators and inverted siphons were solved together with St. Venant equations by Preissmann method with good stability and high precision in the model. Different flow pattern in different opening of the regulators was continuously simulated. In order to implement the simulation and real-time display of the flow movement and transmission in the channel, module technology was employed to construct the hydraulic model of the MRSNWD Digital Channel; multithreading technique was used to couple unsteady-flow model and MRSNWD Digital Channel. It makes the basic database layer, platform layer and application layer of the MRSNWD Digital Channel combined effectively, and construct a comprehensive platform including the analysis of conveyance ability and hydraulic response.The MRSNWD Digital Channel model was employed to study key problems such as safety and stability of MRSNWD conveyance and optimization of operation control for MRSNWD. The phenomena and characteristic of hydraulic response of unsteady flow in main channel under normal and abnormal working conditions were analyzed. The influence of channel depth, section geometric size and the opening of regulators on the stabilization time of channel and fluctuation characteristic of flow is obtained. The characteristics of water level fluctuation in abnormal working conditions are also obtained. Furthermore, feature of hydraulic response in the main channel of MRSNWD at different water-level intervals under downstream control is analyzed and optimized water-level interval under downstream control is obtained. Finally, space dispatching is proposed and preliminary researched.