淹没深度对三自由度波能浮子获能的影响

为明确浮子淹没深度对三自由度浮子装置获能的影响,提出漂浮式与淹没式两种浮子模型,计算并比较在不同淹没深度和波浪条件下浮子的获能特性。浮子模型具有纵荡、垂荡与纵摇3个运动自由度。浮子选用直立圆柱体浮子。淹没深度分别设置为其高度的0.5、1.0、1.5与2.0倍,质量相同。漂浮式浮子模型作为对照,基于线性势流理论与边界元方法,建立浮子水动力学模型,计算浮子水动力学参数及运动响应,并采用线性能量转换(power take-off, PTO)系统阻尼,计算并对比浮子在最优PTO阻尼下的平均输出功率,分析淹没深度对浮子获能的影响。研究结果表明,增大淹没深度可以减小浮子的波浪激励力和平均输出功率。对于三自由度浮子,漂浮浮子在低频波浪下获能特性较好,而具有较小淹没深度的浮子在高频波浪下性能更优。

Power capture influence of the submerged depth for the three-freedom oscillating body wave energy converter

To clarify the power capture influence of the submerged depth for the three-degree-of-freedom(3-DOFs)oscillating buoy wave energy converters, two floating and submerged buoy models were established. Power capture characteristics of the submerged buoys were calculated and compared with different depths and wave conditions. The cylindrical buoy was selected. The submerged depth were 0.5, 1.0, 1.5 and 2.0 times of the buoy’s height. The mass of the buoys were the same. The floating buoy was selected as a comparison. Based on linear potential theory and boundary element method, the hydrodynamic model was established, and the hydrodynamic parameters and kinematic responses of the buoy were calculated. And the optimal average output powers were calculated with linear power take-off(PTO)damping. The effect of submerged depth on the power capture of the buoy was analyzed. The results showed that increasing the submerged depth could reduce buoys wave excitation forces and power absorption. For 3-DOFs buoy, the floating one had a better power capture performance under low frequency waves, while the submerged one with a small submerged depth was better under high frequency waves.