Design And Key Technical Research On No-backwave Wave-current Flume System

Waves and currents impose complex loads on fixed or floating structures and equipment at sea.To reduce the costs and risks of developing offshore structures and equipment,the laboratory equipment is needed which can simulate waves and currents.It is very important to develop a physical simulation test platform for the Marine environment.At present,the types of wave-current flume are relatively single,which is mainly equipped with oblique flush type inlet and piston wave maker.However,the back wave produced by the piston wave maker due to the movement of the wave maker will interfere with the displacement and control of the wave maker,and affect the wave making quality.On the other hand,when the velocity of oblique inlet is high,it will disturb the liquid surface at the top of the flume,cause the energy loss of the water current,affect the wave quality and flow field state in the flume.Therefore,in order to eliminate the negative effects of back wave and liquid level interference,this paper proposes a no-back-wave wave-current flume system,which is composed of a direct flush type inlet and no-back-wave wave maker system.Through the simulation analysis of the flow field characteristics of the water trough,the structure and position controller of the wave maker,verify the effectiveness of the current making system and the wave maker system.The main work of this paper is as follows:Firstly,to study the theories of the design of the wave-current flume system,including the flow field simulation theory and the piston wave making theory.Design the water inlet structure and the no-back-wave wave maker of the wave-current flume,and describe the wave making principle of the wave maker.Put forward the overall scheme of the no-back-wave wave-current flume system.Combined with the technical indexes of the system,determine the design parameters of the current making system and the wave making system,as well as the motion limit position of the wave maker.Secondly,STAR-CCM+ is used to establish the numerical calculation models of oblique type,up-well type and no-back-wave wave-flow flume,and numerical simulation is carried out for the models.Analyze and compare the velocity vector distribution state of the three types of wave-flow flume and the vertical velocity distribution state of the test area under different working conditions.At the same time,comprehensive evaluation of the flow field characteristics of the flume without the maximum wading depth of the wave maker.Thirdly,to design the mechanical structure of the no-back-wave wave maker.To determine the maximum load of the wave maker at the limit position.Carry out statics and modal analysis of key components.Obtain the static performance parameters,natural frequency and vibration mode of the component structure.The structure of the components was optimized to verify the static performance of the optimized structure.Finally,to derive the mathematical model of the no-back-wave wave maker,and the kinematic analysis of the mechanism is carried out by ADAMS software.The input and output data are identified systematically,and to get the kinematic model of the no-back-wave wave maker.To design the active disturbance rejection controller(ADRC)of the no-back-wave wave maker system.The effectiveness and stability of the designed ADRC system are verified by simulation analysis.