破碎波群的显著特征指标

群发性是风浪破碎的显著特征,最近的研究表明风浪破碎研究应该基于波群而不是单个波。本文探讨破碎波群区别于非破碎波群的显著特征指标。依据一系列风浪破碎实验数据,采用多种判据与实验现场目测的破碎标记信号相结合的原则划分破碎波群与非破碎波群,考查波群特征量、单个波几何特征量、局地破碎判据指标、波包络几何特征量以及波群能量结构特征量等5大类28个指标在破碎波群与非破碎波群上的分布差异。结果表明:波陡、峰前波陡、瞬时波面斜率、运动学判据指标和动力学判据指标等在破碎非破碎波群上的分布几乎没有交叠;后两者尤为理想,分布明显分离,是破碎波群区别于非破碎波群的显著指标;而其它各指标在破碎波群非破碎波群上的分布都有不同程度的交叠,不能单独依据它们区分破碎波群与非破碎波群。

The Characteristic Index Distinguishing Breaking Wave Groups From Non-Breaking Wave Groups

The groupness is a significant feature of wind wave breaking.Recent studies have shown that the analysis of wind wave breaking should base on wave group instead of single waves.Based on a series of wind wave breaking experiments,this paper investigates distinguishing characteristic indexes of breaking wave group which are quite different from those of non-breaking wave groups.Breaking wave groups were determined by multi-breaking criteria and mark signal recorded in situ simultaneously.The statistical distributions of 28 indexes on breaking and non-breaking wave groups was discussed,including indexes of wave groups,geometric indexes of single waves,local breaking criteria indexes,geometric indexes of wave envelope and indexes represent wave group energy structure.The results show that for wave steepness,crest front steepness,instantaneous wave slope,index in kinematic and dynamic breaking criteria,few overlaps can be found in their distributions on breaking and non-breaking wave groups,especially for the last two indexes,which in kinematics and dynamic breaking criterion.They are distinguishing characteristic indexes of breaking wave group.Other indexes can’t be used to distinguish breaking and non-breaking wave groups owing to varying degree overlap of their distributions on breaking and non-breaking wave groups.