欧绍武，付世晓

(1. 上海交通大学 海洋工程国家重点实验室，上海 200240; 2. 高新船舶与深海开发装备协同创新中心，上海 200240)

浮式结构物二阶波浪力求解方法比较研究

欧绍武1, 2，付世晓1, 2

(1. 上海交通大学 海洋工程国家重点实验室，上海 200240; 2. 高新船舶与深海开发装备协同创新中心，上海 200240)

对远场法、近场法和中场法这几种常用的二阶波浪力计算方法进行了总结，并结合算例对它们之间的差异进行了研究，重点分析了网格密度、浮体形状、水深等因素的影响。此外，还对全QTF法和Newman近似这两种不规则波中的二阶力计算方法进行了讨论，比较了不同水深条件下两种方法求得的二阶波浪力谱之间的差异。研究结果表明，远场和中场法给出的结果基本一致，且具有较好的数值稳定性；而近场法受网格密度、浮体形状等因素影响较大；Newman近似给出的结果在频率较低时与全QTF法接近，但在频率较高时存在一定的误差。

二阶波浪力；远场法；近场法；中场法；全QTF法；Newman近似

Abstract: The commonly used methods in calculating second-order wave drift forces, such as far-field integration, near-field integration and middle-field integration, are summarized. The difference between these methods are studied by several examples, with special emphasis on element density, model shape and water depth. In addition, the drift forces in irregular sea with different water depths are calculated by both full-QTF method and Newman’s approximate, and the difference between two methods is further discussed through spectrum analysis. The results show that far-field integration and middle-filed integration give similar results with better robustness, while near-field integration is largely influenced by element density and model shape. It also shows that the results given by the Newman’s approximation are close to those by the full QTF method at low frequencies, but with certain errors when the frequency is higher.

Keywords: second-order drift force; far-field integration; near-field integration; middle-field integration; full-QTF; Newman’s approximate

对于海洋结构物而言，在不规则波浪的作用下，受到的波浪力包含一阶和二阶成分。一阶波浪力幅值较大，与波高成线性关系且频率与波浪相同。而二阶波浪力包括定常二阶力、低频二阶力和高频二阶力三部分，幅值相对较小，且与波高的平方成比例。由于二阶波浪力的存在，使得波浪中的海洋结构物不仅存在波频的摇荡运动，而且还存在长周期的漂移运动，这一运动的频率远低于不规则波的特征频率。……