基于粘性无反射数值波浪水池研究波浪作用下双浮体共振问题

Investigation of Wave Diffraction around Two Adjacent Structures Based on Viscous Flow Model

对于存在小间隙的双浮体系统在波浪作用下的共振问题,传统的势流模型由于忽略了流体粘性的影响,往往会严重高估共振现象。鉴于此,论文通过在不可压缩粘性流体的N-S方程中添加质量源项和阻尼项,建立了粘性无反射数值波浪水池,并基于此数值水池对不同频率波浪下的二维和三维双方箱形浮体的水动力特性进行模拟研究。结果表明,对于二维双浮体,论文方法能够准确地对间隙内的波高、作用在浮体上的波浪力及其共振频率进行预报;在共振频率附近,传统势流模型忽略了粘性的影响,相比论文方法会高估间隙内的波高以及波浪力。对于三维双浮体,势流和粘流结果的差异明显小于二维时两者的差异。对比二维和三维结果可以发现:二维双浮体受到的水平和垂向波浪力均存在强烈的共振现象;而三维双浮体受到的垂向波浪力不存在共振现象,而是随入射波频率的增加而单调递减。

For the wave-structure interaction problem of twin bodies in waves,traditional potential method tends to over-predict the resonant phenomenon due to ignorance of fluid viscidity.In view of this,a viscous flow model is established for the present investigation.Based on this model,two-dimensional wave diffraction around twin box-shaped bodies is simulated.Detailed comparison is conducted between the wave tanks with and without structures.Good agreement is found between the present numerical results and experimental data.In the vicinity of the resonant frequency,the present method is more accurate than the potential method.Then we extend the two-dimensional twin bodies system to the three-dimensional system and similar wave-structure interaction is simulated.The difference between the three-dimensional potential and viscous results is found to be much smaller than that in the two-dimensional case.And it is observed that sharp peak responses can still be observed for horizontal forces and waves,but resonance will not take place for vertical forces.