Influence of mean water depth and a subsurface sandbar on the onset and strength of wave breaking

IOCAS-IR > 海洋环流与波动重点实验室

	Influence of mean water depth and a subsurface sandbar on the onset and strength of wave breaking
	Song, JB ; Banner, ML
	2004-04-01
发表期刊	JOURNAL OF PHYSICAL OCEANOGRAPHY
ISSN	0022-3670
卷号	34 期号:4 页码:950-960
文章类型	Article
摘要	Wave breaking in the open ocean and coastal zones remains an intriguing yet incompletely understood process, with a strong observed association with wave groups. Recent numerical study of the evolution of fully nonlinear, two-dimensional deep water wave groups identified a robust threshold of a diagnostic growth-rate parameter that separated nonlinear wave groups that evolved to breaking from those that evolved with recurrence. This paper investigates whether these deep water wave-breaking results apply more generally, particularly in finite-water-depth conditions. For unforced nonlinear wave groups in intermediate water depths over a flat bottom, it was found that the upper bound of the diagnostic growth-rate threshold parameter established for deep water wave groups is also applicable in intermediate water depths, given by k(0) h greater than or equal to 2, where k(0) is the mean carrier wavenumber and h is the mean depth. For breaking onset over an idealized circular arc sandbar located on an otherwise flat, intermediate-depth (k(0) h greater than or equal to 2) environment, the deep water breaking diagnostic growth rate was found to be applicable provided that the height of the sandbar is less than one-quarter of the ambient mean water depth. Thus, for this range of intermediate-depth conditions, these two classes of bottom topography modify only marginally the diagnostic growth rate found for deep water waves. However, when intermediate-depth wave groups ( k(0) h greater than or equal to 2) shoal over a sandbar whose height exceeds one-half of the ambient water depth, the waves can steepen significantly without breaking. In such cases, the breaking threshold level and the maximum of the diagnostic growth rate increase systematically with the height of the sandbar. Also, the dimensions and position of the sandbar influenced the evolution and breaking threshold of wave groups. For sufficiently high sandbars, the effects of bottom topography can induce additional nonlinearity into the wave field geometry and associated dynamics that modifies the otherwise robust deep water breaking-threshold results.; Wave breaking in the open ocean and coastal zones remains an intriguing yet incompletely understood process, with a strong observed association with wave groups. Recent numerical study of the evolution of fully nonlinear, two-dimensional deep water wave groups identified a robust threshold of a diagnostic growth-rate parameter that separated nonlinear wave groups that evolved to breaking from those that evolved with recurrence. This paper investigates whether these deep water wave-breaking results apply more generally, particularly in finite-water-depth conditions. For unforced nonlinear wave groups in intermediate water depths over a flat bottom, it was found that the upper bound of the diagnostic growth-rate threshold parameter established for deep water wave groups is also applicable in intermediate water depths, given by k(0) h greater than or equal to 2, where k(0) is the mean carrier wavenumber and h is the mean depth. For breaking onset over an idealized circular arc sandbar located on an otherwise flat, intermediate-depth (k(0) h greater than or equal to 2) environment, the deep water breaking diagnostic growth rate was found to be applicable provided that the height of the sandbar is less than one-quarter of the ambient mean water depth. Thus, for this range of intermediate-depth conditions, these two classes of bottom topography modify only marginally the diagnostic growth rate found for deep water waves. However, when intermediate-depth wave groups ( k(0) h greater than or equal to 2) shoal over a sandbar whose height exceeds one-half of the ambient water depth, the waves can steepen significantly without breaking. In such cases, the breaking threshold level and the maximum of the diagnostic growth rate increase systematically with the height of the sandbar. Also, the dimensions and position of the sandbar influenced the evolution and breaking threshold of wave groups. For sufficiently high sandbars, the effects of bottom topography can induce additional nonlinearity into the wave field geometry and associated dynamics that modifies the otherwise robust deep water breaking-threshold results.
关键词	Deep-water Behavior Bar Surface Evolution
学科领域	Oceanography
收录类别	SCI
语种	英语
WOS记录号	WOS:000221070100016
引用统计	被引频次：16[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/2486
专题	海洋环流与波动重点实验室
作者单位	1.Univ New S Wales, Sch Math, Sydney, NSW 2052, Australia 2.Chinese Acad Sci, Inst Oceanol, Qingdao, Peoples R China
推荐引用方式 GB/T 7714	Song, JB,Banner, ML. Influence of mean water depth and a subsurface sandbar on the onset and strength of wave breaking[J]. JOURNAL OF PHYSICAL OCEANOGRAPHY,2004,34(4):950-960.
APA	Song, JB,&Banner, ML.(2004).Influence of mean water depth and a subsurface sandbar on the onset and strength of wave breaking.JOURNAL OF PHYSICAL OCEANOGRAPHY,34(4),950-960.
MLA	Song, JB,et al."Influence of mean water depth and a subsurface sandbar on the onset and strength of wave breaking".JOURNAL OF PHYSICAL OCEANOGRAPHY 34.4(2004):950-960.

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