双自由度浮体的CFD模拟与能量吸收特性分析

波浪能装置中浮子的运动性能直接影响装置的能量吸收.采用基于N-S方程的CFD方法建立三维数值波浪水池,对一种特定波浪能装置中的浮子进行时域数值模拟,并与实验对比验证了该方法的可行性.从流场的角度分析浮子运动对周围流体的影响,研究浮子在单自由度垂荡、单自由度纵摇和双自由度垂荡、纵摇时的运动及能量吸收规律.结果表明:浮子在单自由度垂荡和纵摇时,其俘获宽度比随PTO阻尼系数的增大会出现最大值,即俘获宽度比存在最佳PTO阻尼;浮子双自由度运动时其俘获宽度比高于浮子单自由度运动时的俘获宽度比;浮子不同自由度的对比表明,两个自由度在浮子的能量吸收上可以相互影响.

CFD simulation and energy absorption characteristics analysis of a double DOF buoy

In the wave energy converter, the performance of buoy motion can affect the energy absorption of the device directly. A three-dimensional numerical wave tank was built, which was based on CFD method using N-S equation. By simulating the time-domain motion of buoy and comparing with the experimental results, the feasibility of the CFD method was verified. Based on this, the effect of buoy motion on the surrounding fluid was analyzed using the flow field and the energy absorption regular of single and double DOFs was studied. It is shown that the buoy makes heave or pitch motion, the capture width ratio appears the maximum value with the increase of the PTO damping coefficient, the capture width ratio has the best PTO damping, the capture width ratio of double DOF buoy is higher than that of the single DOF buoy, the two DOF can affect each other in the energy absorption by comparing the different DOFs of the buoy.