Experimental Study On Flow-induced Motionand Hydrokinetic Energy Of Two T-section Prisms In Tandem Arrangement

With the continuous growth of China's economy,the national demand for electricity is increasing,the traditional thermal power can not only not meet such a high demand,but also our living environment will cause pollution,so the research on renewable clean energy is imminent.This paper is based on Vortex Induced Vibration for Aquatic Clean Energy system VIVACE?Vortex Induced Vibration for Aquatic Clean Energy?.In this paper,the flow-induced motion and power generation characteristics of series double T-section prisms are studied.By changing tandem T section of upstream and downstream of the oscillator center spacing ratio?L/D=3¹5?and an external resistance tolerance?8??R_L?41??to study the spacing ratio and damping ratio of upstream and downstream T-shaped section respectively the influence of flow induced vibration of the oscillator and power characteristics,and compared with single vibrator T-section analysis.All the tests were carried out in the self-circulation flume of the state key laboratory of hydraulic engineering simulation and state key laboratory,institute of frontier technology,Tianjin university.The Reynolds number range of the tests was 45303?Re?116945?0.516m/s?U?1.332m/s?.Based on the data processing of displacement and voltage time history,the experimental results of amplitude ratio,frequency ratio,power generation and power generation efficiency were given.The main conclusions of the experiment are as follows:?1?For the upstream T-section prism,the change of external resistance has more influence on the fluid-induced motion of the upstream T-section prism than the spacing ratio.External resistor R_L=8?,upstream of the spacing between the T-sections were for the vortex-induced vibration of the vibration characteristics;External resistor R_L=11?,upstream of the spacing between the T-sections vibration performance for hard galloping features;When an external resistor R_L=13?spacing ratio L/D=3 and upstream of the T-section prism?L/D=6?showed soft galloping vibration characteristics,the spacing ratio L/D=9,L/D=12 and L/D=15 T section upstream of vibrator show hard galloping features;Resistance in 16??R_L?41?,the distance upstream of the T-section vibration are characterized by soft galloping features.In general,the larger the external resistance value and the larger the spacing ratio,the better the upstream T-section prisms vibration.?2?For the downstream T-section prism,the influence of spacing ratio on the downstream T-section prism flow vibration is greater than that of the external resistance due to the greater influence of the wake flow of the upstream T-section prism In general,the larger the spacing ratio is,the greater the resistance value of the external resistance is,and the more self-excitation the downstream T-section prism can enter into gallop vibration.In addition,the downstream T-section on vibrator with large spacing ratio is more likely to be excited by the wake flow of the upstream T-section prism,and the wake vibration can even occur.?3?Optimal amplitude ratio in U_r=10.375,flow spacing ratio L/D=15,when an external resistor R_L=31?downstream of T-section on the oscillator,the amplitude ratio A^*=2.34,the corresponding frequency ratio of f^*=0.73.?4?For the upstream and downstream t-section vibrators,with the change of external resistance,the power generation curves intersect with each other,and the law is similar.Resistance in 11?in RL 41?range or less,or less external resistance tolerance,decrease of the power increasing.?5?Under the condition of different spacing ratio,because of the mutual interference between the vibration of the upstream and downstream T-section section vibrators,the upstream T-section section vibrators and the downstream T-section vibrators are inhibited to different degrees.In addition to an external resistor R_L=13?and spacing 3?L/D?6,the upstream T section of vibrator output power increases with the increase of flow velocity,and vibration into the galloping branch,because T-section downstream oscillator.Resistance in 8??RL?13?range,T-section downstream stator power in reduced velocity when U_r acuity 8.5 began to increase.?6?In the tests,the highest active power occurred at U_r=12.25 for L/D=6,R_L=11?,and P_harn=30.12W,corresponding to?_harn=9.08%.The highest efficiency reached in this set of tests was 10.04%.It occurred at U_r=12.25 for L/D=6 and R_L=11?,corresponding to P_harn=21.02W.The active power of UTP and DTP was lower than that of STP in general.It can be concluded that the active power of UTP+DTP was less than twice that the STP,and the optimal active power of two T-section prisms?30.12 W,L/D=6?in the tests was that of single prism?20.12W?,i.e.,1.5 times for R_L=11?.