Hydrodynamic Study Of Buoys Based On Wave Energy

Marine data buoys are one of the effective ways to monitor water quality hydrological parameters and explore marine resources,and are receiving more and more attention from all countries.Buoys often suffer from harsh environments such as wind,waves and currents at sea.How to improve the stability of buoys in waves has become a challenge for all countries;the same with ocean buoys is an offshore drifting device,and its persistent power supply problem limits the development of buoys.This paper mainly designs a small marine data buoy system suitable for offshore.According to the characteristics of ocean wave energy,a wave energy generation device for marine buoys is designed.According to common monitoring requirements,a buoy monitoring system is designed,which mainly includes: data acquisition subsystem,communication transmission subsystem,power supply subsystem and control subsystem;The buoy structure was designed and checked and hydrodynamically analyzed.Main tasks as follows:(1)Designing oscillating water column wave energy generating device,realizing wave energy power supply of buoy.The diameter of the central pipe at the junction of buoy and wave energy power supply has a great influence on the efficiency of wave energy generation.The different values of the radius of the central pipe in wave energy power generation device are simulated and analyzed by CFD software.The results show that increasing the diameter of the central pipe appropriately can effectively improve the efficiency of wave energy conversion.(2)Design the buoy power supply monitoring subsystem to realize the complementary power supply of wave energy and solar energy.According to the overall analysis of the sea condition,the critical working and living environment of the buoy system is defined;the buoy system is designed and the subsystems are selected;the battery capacity is selected according to the power consumption analysis of each system;and the power control system is designed to realize the intelligent complementary power supply between wave energy and solar energy.(3)Designing the structure of the buoy(main buoy,tower and pendulum)and checking and analyzing the geometry and motion parameters of the buoy.The results show that the center of gravity and buoyancy of the buoy meet the stability requirements;the initial stability calculation results meet the criteria in the Code for Stability of Marine Vessels;the natural frequencies of heave and roll exceed the main energy frequencies of waves to avoid resonance.Simultaneously,the simulation results of different radius sizes of the pendulum plate show that the additional mass and wave-following performance of the buoy can be significantly improved by adding the pendulum plate.(4)Through fluid simulation,the hydrodynamic performance of the buoy system is analyzed.The wave power supply buoy is modeled and its parameters are set.The first and second order wave forces,additional mass coefficients,damping coefficients and motion response factor RAO of the buoy system in the two directions of heave and roll are analyzed respectively.The results show that:a)The first and second order wave forces acting on the buoy are relatively small and are within the range of the heave plate.b)The curves of additional mass coefficient and damping coefficient in rolling and heave directions are within a reasonable range.c)The RAO response of the buoy is smaller under JONSWAP wave spectrum.Based on the hydrodynamic analysis of the whole buoy system,the rationality of the overall structure of the buoy powered by wave energy is verified.It provides a good reference for engineering practice.