含透空结构浮体的微幅振荡辐射特性

Radiation of water waves induced by oscillation of floating body with porous structure

基于线性势流理论以及porous-wavemaker理论,针对带有侧立透空薄板、在三自由度(纵荡、垂荡和横摇)内作微幅运动的浮式结构物的波浪辐射问题,利用分离变量法以及边界匹配特征函数展开方法,以解析解的形式,建立该波浪辐射问题的二维无因次理论解析计算模型,得到各流体子区域内速度势函数以及该浮式结构物的无因次附加质量和辐射阻尼系数.分析在不同的透空薄板透水系数下,该浮体的附加质量和辐射阻尼随无因次波长的变化趋势.将部分解析计算结果与现有研究成果进行对比分析,一致性较好,验证了针对该问题提出的解析计算模型的正确性.研究结果表明,在低频范围内,透水薄板的透水系数对该浮式结构物的水动力系数的影响较明显;随着透水能力的增大,该浮式结构物的水动力系数呈现出减小的趋势,这对改善浮式结构物的稳定性具有重要意义.

The wave radiation issues of oscillating floating body with vertical porous walls in three degrees of freedom (surge,pitch and roll) were analyzed based on the linear potential-flow and the porous-wavemaker theories by applying separate variable and boundary matched eigenfunction expansion methods.The two-dimensional dimensionless analytical models were theoretically developed to get velocity potentials of each fluid sub-domain as well as the dimensionless added masses and radiation damping coefficients of the floating body.The variation trend of the added masses and damping coefficients of the floating body versus the dimensionless wavelength were analyzed under the conditions of different porous-effect parameters associated with porous walls.Some cases of the presented analytical solutions matched well with the published results,which verified the correctness of the analytical solutions proposed for this radiation issue.Results showed that the dimensionless porous-effect parameter of porous wall had an obvious influence on the hydrodynamic coefficients of the floating body in the low frequency area.The hydrodynamic coefficients of the floating body decreased with the increase of porous-effect parameters, which was significant for the improvement of the stability of the floating body.