Generation and evolution features of L2-type crescent waves in laboratory conditions

A series of experiments on generation and evolution of L2-type crescent waves are performed. The examined influencing factors includes the effects of different experimental setups, competition of class I and class II instabilities and the effects of finite water depth and wave steepness. The most unstable perturbation waves are introduced as a laboratory experiment technique of crescent wave generation. The measured critical wave steepness for triggering crescent waves is obtained and compared with theoretical results. The evolution features of L2-type crescent wave and Benjamin-Feir instability are discussed.