一种新的非线性波浪周期概率分布
A new probability distribution of non-linear wave periods
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摘要: 在最大熵原则的基础上,通过解一条件变分问题,导出一种新的适用于描述非线性波浪周期T统计分布的概率密度函数。这种概率分布有如下的优越性:(1)该分布的参数是由无因次周期的m(m为正数)阶分布矩得出,从而周期的信息熵达到最大,故适用于描述波浪周期的非线性;(2)该分布有4个参数,从而更能符合最大熵原则;(3)该分布形式简单且其参数容易由已知观测数据确定,从而便于理论和实际应用。用实验室风浪槽中不同风速下和不同风区处实测的风浪的周期数据对此概率密度函数进行验证,结果显示概率密度函数与各组实测数据符合良好,且优于Longuet-Higgins导出的周期分布。Abstract: Based on the maximum entropy principle, a probability density function (PDF) for the periods of random waves is derived through solving a variational problem subject to some quite general constraints. The main points of the method are as follows: (1) the parameters in the function are expressed m-th distribution moments (m is positive number).This PDF maximizes the information entropy of T , so it is well competent for describing the distribution of T of nonlinear sea waves with large uncertainty; (2) this PDF have four parameters , so it is well competent for the maximum entropy principle; (3) its parameters can be simply determined from available data. Comparisons between the PDF and the observed distributions of periods data made from wave records measured in a wind-wave tunnel show well satisfying agreements and is more favorable than the Longuet-Higgins PDF.
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Key words:
- non-linear wave /
- the maximum entropy principle /
- periods
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