Research On The Wave Generation And Active Absorption Based On Rotary Valve Control

Wave action is the main load of marine engineering,hydraulic engineering,ships and marine equipment.In order to expand the development and utilization of marine resources,accurate reproduction of wave effects on offshore objects is a hot issue of concern for researchers.In order to meet the demand of complex wave generation and the function of active wave absorption,based on the previous rotary valve controlled excitation device,the rotary valve controlled wave creation and active wave absorption methods are proposed,and the following studies are conducted around the wave characteristics generated by it.1.A rotary valve controlled regular wave generation model is established to study the relationship between the wave-making waveform and structural parameters and control parameters of the new driving system.Revealing the law that the wave-making plate amplitude and motion frequency are continuously adjustable and can be controlled independently,and it is easy to generate various target rule waves.The hydraulic transfer functions of wavemaker under piston-type and flap-type are derived,The theoretical waveforms of the rotary valve controlled wavemaker are calculated and solved.2.The experimental platform was built to study the wave generation at different wave frequencies,different valve openings and different supply pressures,and the wave generation experiments were carried out for piston-type and flap-type respectively.3.On the base of regular wave generation,two methods of irregular wave generation are proposed based on the principle-of wave superposition.Using the characteristics of different frequency waves traveling at different rates,low frequency waves are generated to catch up the high frequency wave by controlling the core rotation frequency of the rotary valve,so that the two waves converge at a certain position and superimpose to generate waves with significant wave height and conform to the definition of the freak waves.In order to facilitate the generation of white noise waves with equal amplitude but different frequencies,mathematical models of white noise wave generation methods corresponding to the wave-making modes of piston-type and flap-type are established respectively,and the variation laws of the required control parameters are derived.According to the theoretical parameters,the white noise waves with different energy densities are obtained experimentally.4.A new method of active wave absorption with rotary valve control is proposed to absorb the secondary reflected waves in the water tank to improve the simulation accuracy of wave generation test.The mathematical model of active wave absorption is established,and the theoretical wave surface and valve opening variation law are obtained when active absorption is performed.According to the obtained law,the secondary reflected waves are absorbed by controlling the axial opening of the valve orifice to make the hydraulic cylinder carry out the wave making experiment with additional absorption displacement on the wave making displacement.The experimental results show that the larger the initial traveling wave height is,the larger the additional absorption displacement required.This method can effectively absorb the secondary reflected waves in the sink,so that only the traveling and reflected waves are left in the sink,and finally a stable standing wave is formed.In summary,the paper proposes a new wave generation method and active wave absorption method,which can meet the wave characteristics and test accuracy in the test area,and can help develop wave generation theory and experimental methods.Figure[40]table[10]reference[81]...