随着全球气候变化，极端大浪频发，而极端大浪常常伴随着波浪破碎的发生。破碎波，特别是卷破破碎波能够对海上结构物产生巨大的作用力，对结构物的安全造成致命威胁。而圆柱是海洋工程中典型的结构型式，因此开展破碎波对圆柱作用的研究十分必要。波浪破碎及其作用过程极其复杂，物理模型实验是对其进行深入细致研究的最有效方法。但在物理模型实验中，模型与原型的差异使得物理模型实验面临着比尺效应的问题，从而造成实验结果差异较大。本项目拟开展不同比尺的卷破波对圆柱作用的物理模型试验，分析破碎波对圆柱作用力的比尺效应。通过粒子图像测速法（PIV）和气泡图像测速法（BIV）对破碎波与圆柱相互作用过程的三维流场进行测量分析，分析流场的三维结构特征，从而改进破碎波对圆柱冲击力计算方法。最终，通过对试验数据的综合分析，得到考虑比尺效应的破碎波对圆柱作用力的计算方法。这是一项极具挑战的突破性研究。

With the change of global climate change, appearance of extreme waves are more and more often. Extreme waves are always accompanied with breaking events. Breaking waves, especially for plunging breaker, can induce very large impacting forces and threat the safety of marine structures. On the other hand, Cylinder-type structures are one of the most common structures in ocean engineering. Therefore, it is necessary to carry out research work on this aspect. However, as wave breaking and its interaction with structures are very complex processes, there are no a theoretical method or a numerical model having the ability to deal with it. Physical experiment is an effective method and always used to study wave breaking. However, scale effect, which is caused by reducing the scale of prototypes in experiment, is a challenge and it can not be negligible in scaled-physical experiments. The existing scale effect sometimes can induce large deviations between experimental and prototype results. In the present project, the scale effects of plunging breaking waves and its impact on cylinders will be carried out. Particle Image Velocimetry (PIV) and Bubble Image Velocimetry (BIV) will be adopted to to measure the velocity fields around the cylinder during breaking wave impacing. Then, the characteristics of three dimensional velocity fields can be resolved and used to improve the impact force models. Finally, a method to calculate breaking impacting forces on cylindrical structures will be proposed by considering the scale effect. This is really a very challenging and breakthrough study.