基于小波变换的畸形波海况时频分析研究

Research on the Time-Frequency Analysis of Freak Waves Based on Wavelet Transform

在随机海浪条件下,基于修正的四阶非线性薛定谔方程(m NLS)能够有效地模拟畸形波的非线性演化,文中利用小波变换对演化过程进行分析,并对时频谱特征参数(能量集中区域在时域和频域的分布范围)以及能量集中度进行了定量描述,结果表明,当畸形波出现时,能量可以由低频向高频扩散且能量集中度相对较大。

Under the condition of random ocean waves, the four-order modified nonlinear Schrodinger（mN LS）equation can effectively simulate the nonlinear evolution of freak waves. In this paper, the evolution process is analyzed by using the wavelet transform. The time-frequency spectrum characteristic parameters（the distribution range of energy focused regions in time domain and frequency domain） and the degree of energy concentration have been also described in a quantitative way. Results show that energy can diffuse from the low frequency domain to the high frequency domain and the energy concentration degree is relatively large when freak waves occur.