Numerical Study On Self-Excited Vibration Energy Harvesting With Interference

Wind power generation solar power and water storage power generation water power have the disadvantages of high requirements for the construction environment and high maintenance costs.The results show that a large amount of fluid kinetic energy is stored in the ocean,which can be converted into electricity by means of flow induced vibration.Therefore,the marine energy harvesting technology has become the main research direction of power generation.In addition,most of them work in the form of energy harvester cluster and have the advantages of strong power supply pertinence and low construction cost,so it is of great significance to optimize their comprehensive performance by means of interference effect.Based on the above research background,the fluid structure coupling model of self-excited vibration of energy harvesting cylinder under the interference effect is established in this paper and the numerical simulation of the model is carried out,and then the output power,energy capture efficiency and power density of the flow-induced vibration energy harvester are calculated on the basis of the sinusoidal hypothesis.The main research contents and conclusions are as follows:(1)The force and vibration characteristics of energy harvesting cylinder under the cylindrical interference,near wake structure interference,channel interference are studied.The results show that the existence of the interference will induce the vortex induced vibration-galloping coupling vibration,improve the output power and energy harvesting efficiency of the flow-induced vibration energy harvester,effectively expand its effective working bandwidth,and finally achieve the improvement of its comprehensive performance.(2)The vibration of the energy hargvesting cylinder with different interference distance and flow velocity is compared.The results show that the cylindrical interference can induce the energy hargvesting cylinder to vibrate with multiple harmonics,and then enhance the output power of the flow-induced vibration energy harvester.The results show that the maximum output power under cylindrical interference will reach 2.12 W at U*=12,HS=3D,TS=1D.(3)The influence of the distance between the cylinders on the vibration of the energy hargvesting cylinder is studied.The results show that the vibration frequency and the vibration speed of the energy hargvesting cylinder will increase obviously after the near wake structure interference is introduced into the flow field,and the maximum energy harvesting efficiency and the power density of the flow-induced vibration energy harvester will also be significantly improved,so as to ensure the working efficiency of the flow-induced vibration energy harvester.The results show that the maximum power density of the flow-induced vibration energy harvester is 12.32 W/m~2.(4)The influence of the size and position of the interference channel and the initial position of the energy hargvesting cylinder on the energy harvesting characteristics of the flow-induced vibration energy harvester is analyzed.The results show that when the initial position of the energy hargvesting cylinder is at the throat of the disturbance nozzle,the enhancement effect of the output power and the energy harvesting efficiency of the flow channel interference flow-induced vibration energy harvester is the most obvious.At this time,the amplitude and vibration frequency of the energy harvesting cylinder are significantly increased,so the channel interference can optimize the effective working bandwidth,output power and energy harvesting efficiency of the flow-induced vibration energy harvester at the same time.When U*=3,d=550 mm,y=4.5D,the maximum energy harvesting efficiency will be 47.38%.