scholarly journals Bragg Reflection of Long Waves Generated by Short Wave Groups on a Sloping Beach

2003 ◽  
Vol 36 (3) ◽  
pp. 413-422
Author(s):  
Jae-Sang Jung ◽  
Yong-Sik Cho
Keyword(s):  
Bragg Reflection ◽  
Short Wave ◽  
Long Waves ◽  
Wave Groups ◽  
Sloping Beach

Long waves induced by short-wave groups over an uneven bottom

1984 ◽  
Vol 139 ◽  
pp. 219-235 ◽  
Author(s):  
Chiang C. Mei ◽  
Chakib Benmoussa
Keyword(s):  
Group Velocity ◽  
Short Wave ◽  
Long Waves ◽  
Finite Region ◽  
Variable Depth ◽  
Wave Groups ◽  
One Dimensional ◽  
Uneven Bottom ◽  
Short Waves ◽  
Horizontal Bottom

Unidirectional and periodically modulated short waves on a horizontal or very nearly horizontal bottom are known to be accompanied by long waves which propagate together with the envelope of the short waves at their group velocity. However, for variable depth with a horizontal lengthscale which is not too great compared with the group length, long waves of another kind are further induced. If the variation of depth is only one-dimensional and localized in a finite region, then the additional long waves can radiate away from this region, in directions which differ from those of the short waves and their envelopes. There are also critical depths which define caustics for these new long waves but not for the short waves. Thus, while obliquely incident short waves can pass over a topography, these second-order long waves may be trapped on a ridge or away from a canyon.

The generation of surface waves over a sloping beach by an oscillating line source

1976 ◽  
Vol 79 (3) ◽  
pp. 573-585 ◽  
Author(s):  
Clare A. N. Morris
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Line Source ◽  
Short Wave ◽  
Long Waves ◽  
Edge Waves ◽  
Wave Regime ◽  
Wave Solutions ◽  
Sloping Beach

AbstractA line source whose strength varies sinusoidally with time and also with the co-ordinate measured along its length is situated parallel to the shoreline of a beach of angle ¼π0. Both long-and short-wave solutions are found. It is shown that for certain positions of the source, long waves are not radiated to infinity, while in the short-wave regime, the solutions take the form of edge-waves, with resonances occurring at certain wavenumbers. Computations of the free-surface contours are presented for a range of wavenumbers.

Transmission of Long Waves Induced by Short-Wave Groups Through a Composite Breakwater

2001 ◽  
Vol 43 (2) ◽  
pp. 83-97 ◽  
Author(s):  
Akter Hossain ◽  
Wataru Kioka ◽  
Toshikazu Kitano
Keyword(s):  
Short Wave ◽  
Long Waves ◽  
Wave Groups

scholarly journals Generation, Transformation, and Scattering of Long Waves Induced by a Short-Wave Group over Finite Topography

2011 ◽  
Vol 41 (10) ◽  
pp. 1842-1859 ◽  
Author(s):  
Qingping Zou
Keyword(s):  
Analytical Solutions ◽  
Wave Train ◽  
Short Wave ◽  
Long Waves ◽  
Wave Group ◽  
Wave Groups ◽  
Long Wave ◽  
Wave Orbital Velocity ◽  
Variable Water ◽  
Horizontal Bottom

Abstract Second-order analytical solutions are constructed for various long waves generated by a gravity wave train propagating over finite variable depth h(x) using a multiphase Wentzel–Kramers–Brillouin (WKB) method. It is found that, along with the well-known long wave, locked to the envelope of the wave train and traveling at the group velocity Cg, a forced long wave and free long waves are induced by the depth variation in this region. The forced long wave depends on the depth derivatives hx and hxx and travels at Cg, whereas the free long waves depend on h, hx, and hxx and travel in the opposite directions at . They interfere with each other and generate free long waves radiating away from this region. The author found that this topography-induced forced long wave is in quadrature with the short-wave group and that a secondary long-wave orbital velocity is generated by variable water depth, which is in quadrature with its horizontal bottom counterpart. Both these processes play an important role in the energy transfer between the short-wave groups and long waves. These behaviors were not revealed by previous studies on long waves induced by a wave group over finite topography, which calculated the total amplitude of long-wave components numerically without consideration of the phase of the long waves. The analytical solutions here also indicate that the discontinuity of hx and hxx at the topography junctions has a significant effect on the scattered long waves. The controlling factors for the amplitudes of these long waves are identified and the underlying physical processes systematically investigated in this presentation.

Influence of Offshore Reefs on Low-Frequency Waves During Harbor Resonance

2017 ◽  
Author(s):  
Junliang Gao ◽  
Chunyan Ji ◽  
Xiaojian Ma
Keyword(s):  
Low Frequency ◽  
Resonant Mode ◽  
Short Wave ◽  
Long Waves ◽  
Boussinesq Model ◽  
Wave Groups ◽  
Frequency Wave ◽  
Wave Separation ◽  
The Given ◽  
Low Frequency Waves

In this paper, a fully nonlinear Boussinesq model is used to simulate the shoreward propagation of bichromatic wave groups over different fringing reef topographies and the subsequent low-frequency oscillations inside a harbor. Based on a low-frequency wave separation technique, the effects of the reef-face slope and the reef ridge on the bound and free long waves inside the harbor and their relative components under the condition of the lowest resonant mode are systematically investigated. For the given harbor, the given reef ridge and the range of the incident short wave amplitudes and the reef-face slopes studied in this paper, results show that the amplitude of the free long waves inside the harbor increases with the reefface slope, while the bound long waves inside the harbor is insensitive to the variation of the reef-face slope. The existence of the reef ridge can notably restrain the bound long waves inside the harbor when the incident short wave amplitudes are large, while it has little influence on the free long waves inside the harbor.

Long wave generation by the shoaling and breaking of transient wave groups on a beach

2006 ◽  
Vol 462 (2070) ◽  
pp. 1853-1876 ◽  
Author(s):  
T.E Baldock
Keyword(s):  
Shallow Water ◽  
Water Waves ◽  
Surf Zone ◽  
Laboratory Data ◽  
Short Wave ◽  
Long Waves ◽  
Transient Wave ◽  
Wave Groups ◽  
Spatial Gradients ◽  
Long Wave

This paper presents new laboratory data on the generation of long waves by the shoaling and breaking of transient-focused short-wave groups. Direct offshore radiation of long waves from the breakpoint is shown experimentally for the first time. High spatial resolution enables identification of the relationship between the spatial gradients of the short-wave envelope and the long-wave surface. This relationship is consistent with radiation stress theory even well inside the surf zone and appears as a result of the strong nonlinear forcing associated with the transient group. In shallow water, the change in depth across the group leads to asymmetry in the forcing which generates significant dynamic setup in front of the group during shoaling. Strong amplification of the incident dynamic setup occurs after short-wave breaking. The data show the radiation of a transient long wave dominated by a pulse of positive elevation, preceded and followed by weaker trailing waves with negative elevation. The instantaneous cross-shore structure of the long wave shows the mechanics of the reflection process and the formation of a transient node in the inner surf zone. The wave run-up and relative amplitude of the radiated and incident long waves suggests significant modification of the incident bound wave in the inner surf zone and the dominance of long waves generated by the breaking process. It is proposed that these conditions occur when the primary short waves and bound wave are not shallow water waves at the breakpoint. A simple criterion is given to determine these conditions, which generally occur for the important case of storm waves.

GENERATION OF LONG WAVES BY SHORT WAVE GROUPS

2003 ◽  
Author(s):  
Ap van Dongeren ◽  
Henk Jan Bakkenes ◽  
Tim Janssen
Keyword(s):  
Short Wave ◽  
Long Waves ◽  
Wave Groups
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