Velocities and accelerations in breaking waves

The unexpected occurrence of unusually large waves has been documented on numerous occasions. While little is known about the statistics of these waves, even less is known of the dynamical conditions under which they occur. Nonlinear interactions among individual waves travelling within a group have been identified as an important mechanism in the formation of giant waves in the ocean. In this study, the non-linear packet-focusing technique is used to generate steep, plunging waves in a laboratory flume. The kinematics of these waves are measured just up-wave of the onset of plunging, and these results are compared to those of a superposition model, a modified stretching model, and a model based on Stokes 3^rd order developed for the present study. The present model represents the velocity beneath the plunging breakers significantly better than the two other models.