Study On The Hydrodynamic Characteristics Of Sudden Expansion Canal And Its Influence On Fish Swimming Behavior

With the rapid development of social economy,the human in the river to build the dam,dam,dam,a large number of brake and other water conservancy projects,to meet the demand for flood control,power generation,water supply,etc at the same time,the river has also changed the original hydrological and hydrodynamic conditions of fish habitat also change accordingly.Sudden enlargement downstream boundary layer separation is the important feature of the water flow in open channel flow and,similar to the water flow often appear in the spur dike,riparian outstanding rock,brake weir,fish passage facilities at the sudden enlargement fish hole and power plant tailrace section downstream,fish are often encountered or gather here,so the sudden enlargement for fish swimming behavior of open channel flow is necessary.Based on the hydrodynamics and fish kinematics cross disciplines,by means of flume experiment and numerical simulation at the sudden enlargement in the combination of hydrodynamic characteristics of flow in open channel and the impact on the fish swimming behavior research,the sudden enlargement at the sudden enlargement by simplifying the open channel for unilateral type,studied at the sudden enlargement three five different size and characteristics of the flow velocity of hydrodynamic characteristic and the working condition of a total of 15 fish swimming behavior characteristics.The main content and achievements of this paper include the following aspects:(1)collected and sorted out a large number of domestic and foreign relevant research data,and summarized and analyzed the research results on fish movement,fish habit,hydrodynamic characteristics of sudden expansion canal,etc.(2)the selection of object of xi flow sex freshwater fish in the water tank installed at the sudden enlargement unilateral open channel model,carry out to flow under the condition of different length fish swimming behavior flume experiment,using high.speed cameras fish swimming behavior of image,the animal behavior analysis of fish swimming mode and range.(3)software simulation was used to calculate the hydrodynamic characteristics of the abrupt expansion canal,and the characteristic parameters of flow velocity,vortex volume,turbulent kinetic energy and flow field structure of various working conditions were analyzed.The characteristics of velocity field and vorticity field in main active areas of fish under different boundary layer separation and reattachment flow are analyzed.(4)the analysis it is concluded that the two types of swimming fish,using the method of statistical analysis research at the sudden enlargement open channel structure,to flow velocity and the hydrodynamic parameters on the influence of the fish swimming mode,it is concluded that sudden enlargement boundary layer separation flow in open channel flow and influence law of fish swimming mode.This study has certain reference significance to the research results of fish swimming behavior under the condition of rich complex water flow,the restoration of micro.water environment of fish habitat and the design of crossing facilities.