湍流强度对涡激振动潮流能转换装置振子响应影响研究

STUDY ON TURBULENCE INTENSITY INFLUENCE ON CYLINDRICAL OSCILLATOR RESPONSE OF VIV TIDAL ENERGY CONVERSION DEVICE

在实海况下,湍流会对涡激振动潮流能转换装置产生影响。为研究湍流强度对涡激振动潮流能转换装置圆柱振子的影响规律,采用SST k-ω湍流模型,通过数值模拟方法在均匀流、湍流强度分别为5%和10%共3种条件下,分析涡激振动潮流能转换装置圆柱振子的振幅比、频率比、升阻力系数的变化情况。结果表明:随着湍流强度的增加,在上部分支振子的振幅比下降,振幅的锁定区域相对均匀流略微变窄;在初始分支,振子在湍流时比均匀流时起振流速高,起振时间长。当约化速度Ur> 4.08时,振子在湍流状态下的升力系数比均匀流时低;当湍流强度为10%时,阻力均值在整个区间比均匀流时小。从能量利用角度分析,振子在上部分支均匀流运动时有效功率比湍流时高。

Tidal energy converters running in the sea would be subjected to the effects of the turbulence. In order to study how turbulent intensity affects the cylindrical oscillator of a tidal energy converter based on vortex-induced vibration(VIV)mechanism,a SST k-ω turbulence model is built to simulate the performance parameters of a VIV tidal energy converter such as amplitude ratio,frequency ratio and lift-drag coefficient of the cylindrical oscillator in the conditions of uniform flow,and turbulence with intensity of 5% and intensity of 10% respectively. The results show that the amplitude ratio of oscillator decreass at the upper branch,and the relatively uniform flow in the locked region of the amplitude becomes slightly narrower with the turbulence intensity increase. At the initial branch,the oscillator has a higher start-up flow velocity and longer starting time in turbulent. The lift coefficient of the oscillator in the turbulent flow is lower than that in the uniform flow,under the conditions of reduced velocity Ur> 4.08. The mean value of the resistance is smaller than that in the uniform flow when the turbulence intensity is 10%. Comparing energy conversion performances,the effective power of the oscillator in uniform flow is higher than that in turbulence at the upper branch.