Experimental Study On Flow Induced Vibration Piezoelectric Energy Harvesting Based On Bionic Structure

With the application of low power dissipation products,such as wireless sensor network technology,MEMs and portable electronic devices becoming more and more extensive,the traditional energy supply method cannot meet the sustainable power demand.Therefore,how to continuously supply energy for low energy consumption products is an important problem to be solved urgently.In recent years,Fluid Induced Vibrating Piezoelectric Energy harvesting?FIVPEH?,as an environmentally friendly,sustainable and efficient energy capture technology,has become a research focus.In this paper,based on the bionics theory and combined with the fluid-solid-electric coupling mathematical model,the vibration and energy capture characteristics of bionic structures were analyzed.To explore the features of energy harvesting with different biomimetic structures,in this paper,the protrusions,pits,passive turbulence control?PTC?and bird-like head structures were manufactured and used in wind tunnel experiments based on the existing smooth bluff body.The variation regularities of output voltage,displacement,vibration frequency and output power under different wind speed,different inclination angle and different load were researched from the perspective of energy harvesting,and the mechanism of different biomimetic structures to enhance or inhibit energy harvesting efficiency is revealed.The main conclusions of this paper are as follows:?1?Firstly,the biomimetic cylinders with protrusions and pits on the surface were studied in the wind tunnel experiment.Compared with the smooth bluff body energy harvester,the pits structure energy harvester generally has a strong characteristic of capturing energy.The critical speed is reduced from 1.8 m/s to 1 m/s,and the bandwidth increased from 39.3%to 51.4%.The maximum output voltage reached to 47 V with the optimal load R_opt=0.8 M?.In contrast,the energy harvesting characteristics of hemispherical protrusions are intricate.The measured voltage of the hemispherical bionic energy harvester was much smaller than that of a smooth cylinder,the peak voltage is below 15 V,and the bandwidth is narrow.?2?secondly,the equivalent circuit modeling is adopted to study the cylinder with PTC on its surface.It is shown that U_crfirst increases and then decreases as the load resistance increases in ac circuit,while U_crgradually decreases with the increase of the load in dc circuit.The galloping will occur at any value of resistance with the wind speed reaches the maximum value of U_cr.In addition,the galloping will enter the lock-in region at U?U_cr,and the output voltage and power increase with the increase of wind speed,while the power increases first and then decreases with the increase of resistance.Furthermore,the growth rate tends to decrease at a high wind speed.Compared with AC circuits,the optimal load is increased from 1.1 M?to 2.0M?in DC circuits,at the same time,the peak power reduced from 0.08 m W to 0.04m W.Compared with VIVEH,the maximum output power and peak voltage of GEH-PTC are increased by 93%and 66.7%respectively at the same wind speed range.Compared with the weak coupling,the displacement of the strong coupling is increased by 125%.?3?Finally,the bionic bluff body with bird-like structure was studied,and the results show that the bionic structure has the most prominent energy harvesting characteristics with the inclination angle is 30°for bionic cylinders,and the response characteristics gradually decrease with the decrease of inclination angle.In addition,the bandwidth of the bionic structure is significantly improved compared to the smooth cylinder,and the optimal load is 0.5 M?.Conversely,the output voltage and power of the bionic square column are smaller than those of the smooth square column,and the optimal load is 0.6 M?.