Two-dimensional Focusing Limit Wave Simulation Study

Because the process of wave breaking is rather complex, neither theoretical nor numerical simulation has ever been adequate to describe the kinematics and dynamics of wave breaking fully. Field observations have also been inadequate due essentially to the randomness in the spatial and temporal occurrences of wave breaking. So experimental study to examine the configuration of focusing wave breaking is a primary signification.Considering the principal that long waves propagate faster and short waves propagate slower, the method for numerical and physical simulation of two-dimensional focusing waves is given in this paper. The control software for wave maker system is developed. The focusing wave properties are investigated through physical experiments. Two kinds of frequency spectra were involved in the research. The first is called constant wave amplitude and the second is called constant wave steepness. The characteristics of the focusing waves, such as amplitude, energy dissipation, parameter of wave surface . is studied. The results give the effect of central frequency, frequency bandwidth, and frequency spectrum on the characteristics of focusing wave.In addition, the numerical model developed in the thesis is called high-order spectral method, which introduces wave making boundary condition and overcomes the shortcoming of spectral method, which only gives original condition. The governing equation is based on the Laplace equation and original non-linear boundary condition. The numerical calculated results are compared with the linear theoretical results for waves with small amplitude and experimental results in the thesis. The identity of the corresponding results means that the model can be used to simulate the two-dimensional wave focusing.