白浪覆盖率模式中参量的研究

THE PARAMETERS IN WHITECAP COVERAGE MODEL

在波面位移为正态过程的假定下,推导出一种以平均周期和风速为参量的白浪覆盖率公式W=1-Φ〔5.11094〔T/U10〕0.7576〕。依据摩擦风速和U10的表达式,进一步推导出白浪覆盖率依赖于摩擦风速的形式W=1-Φ〔0.5227〔T/U*〕0.7576〕。考虑到在实际应用中,经常需要用波龄描述波浪的状态,将白浪覆盖率表示成一种形式简单的波龄的函数W=1-Φ(3.6496ξ0.7576),与Monahan等的海上测量数据符合良好。

A simple formula is analytically derived based on a Gaussian wave field, which is used to estimate the spatial fraction of breaking sea surface at an instant time, i.e., whitecap coverage W. The resulting whitecap coverage is related to wind speed and wave average period. According to the relation between friction speed U, and U10, this derived formula is further expressed with U,. As a wave age is often used to describe the wave state in practice, whitecap coverage is expressed as a simple function of the age. The results of the new model and regarding field data agreed well.