The Study On Hydraulic Characteristics And Scour Mechanism Of Spur Dike

Spur dike is a kind of main regulation structure that is widely used in channel regulation engineering for controlling the shape of the nature river. Some complex flow characteristics such as flow separation, circumfluence appears around spur dikes. It is of great importance for the design of channel regulation structure to explore the effect of spur dikes on flow, and to study the flow structure and the distribution disciplinarian of pressure near the spur dike. The work in the thesis is studied combining with the research project-key scientific and technical project on west China transportation of the period "Tenth Five".Based on brief review and commentary on hydraulic characteristics of local flow field around spur dike, pressure of spur dike and scour mechanism, three physical experiments about fixed bed model, local mobile bed model and pressure on spur dike and runway near the spur dike are undertaken respectively on purpose used organic glass as spur dike, and two physical experiments about local mobile bed model and protecting runway near the spur dike are undertaken respectively on purpose used discrete stone as spur dike.With the aid of the method of theoretical analysis and the model experiment, hydraulic characteristics of local flow field of spur dike are discussed in detail. The distribution disciplinarian of gross dynamic hydraulic pressure and fluctuating pressure on faceplate faced flowing direction and runway near the spur dike, and influencing factors are analyzed. Through fast Fourier transforms (FFT), to transform the time domain distribution of the velocity of flow and the pressure as the frequency domain distribution, to use unified method which the time domain and the frequency domain, research pulsation kinetic energy and fluctuation pressure distributed rule. After drawing the pulsation kinetic energy and the fluctuation pressure distribution isoline as well as the topographic diagram of the scour pit, three reciprocities are studied. Scour mechanism around the spur dike and the process of scour pit and its the influence factor are investigated. The relation of Karman vortex and scour around the spur are studied. The ascertained method of area and volume of the scour pit are given.