球体波能转换装置捕获能量的理论研究

球体波能转换装置在波浪的激励下可以同时在水平和竖直两个模式振荡。基于线性微幅波浪和势流理论,将波浪与球体相互作用简化为球体固定不动,波浪绕过球体和球体在静止流体中运动。线性叠加以后得到总的速度势,计算出球体波能转换装置的平均功率和能量俘获宽度因子的解析表达式。理论研究表明:装置与波浪运动的相位差是影响波能的最重要的参数,最优相位差为-π/2,并且给出了最优相位差调节的理论表达式。另外,对波长、波幅、球体半径、水深和球心距静水面的距离等因素也进行了分析。

Analytical study of power capture of spherical wave energy converts in two modes

A floating spherical wave energy converter submerged under the water surface is studied. The con-verter can oscillate in both horizontal and vertical modes induced by waves and transfer mechanical energy forward by hydraulic cylinders. Based on the linear potential theory of airy waves, the interaction of the waves and the wave energy converters can be divided into two parts. One is flow past a fixed spherical body. The other is a spherical body moving in fluid at rest. By linear superposition of the two parts of velocity po-tential, the final velocity potential is achieved. Then the time-averaged power capture and power capture width ratio is calculated. Different parameters that affect the efficiency of wave energy harvesting are ana-lyzed. The optimal phase difference between the motion of converters and water particles is obtained with a value of -π/2. And phase control is needed to keep the optimal phase difference for different waves. The radius of the spherical body, the wave length and wave amplitude and water depth, as well as the distance of the center of the wave energy converter from the surface, have effects on the efficiency of power capture.