Surface gravity water waves

2015 ◽  
pp. 147-180
Keyword(s):  
Water Waves ◽  
Surface Gravity

Surface Gravity Waves

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Gravity Waves ◽  
Water Waves ◽  
Water Surface ◽  
Wave Pattern ◽  
The Body ◽  
Surface Gravity ◽  
Shallow Water Waves ◽  
Ship Waves ◽  
Surface Gravity Waves ◽  
Basic Fluid

This chapter deals with the underlying mathematics of surface gravity waves, defined as gravity waves observed on an air–sea interface of the ocean. Surface gravity waves, or surface waves, differ from internal waves, gravity waves that occur within the body of the water (such as between parts of different densities). Examples of gravity waves are wind-generated waves on the water surface, as well tsunamis and ocean tides. Wind-generated gravity waves on the free surface of the Earth's seas, oceans, ponds, and lakes have a period of between 0.3 and 30 seconds. The chapter first describes the basic fluid equations before discussing the dispersion relations, with a particular focus on deep water waves, shallow water waves, and wavepackets. It also considers ship waves and how dispersion affects the wave pattern produced by a moving object, along with long and short waves.

scholarly journals Quantum Mechanical and Optical Analogies in Surface Gravity Water Waves

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 96 ◽  
Author(s):  
Georgi Gary Rozenman ◽  
Shenhe Fu ◽  
Ady Arie ◽  
Lev Shemer
Keyword(s):  
Quantum Mechanics ◽  
Gravity Waves ◽  
Water Waves ◽  
Water Wave ◽  
Wave Packets ◽  
Theoretical Models ◽  
Surface Gravity ◽  
Finite Width ◽  
Self Healing ◽  
Surface Gravity Waves

We present the theoretical models and review the most recent results of a class of experiments in the field of surface gravity waves. These experiments serve as demonstration of an analogy to a broad variety of phenomena in optics and quantum mechanics. In particular, experiments involving Airy water-wave packets were carried out. The Airy wave packets have attracted tremendous attention in optics and quantum mechanics owing to their unique properties, spanning from an ability to propagate along parabolic trajectories without spreading, and to accumulating a phase that scales with the cubic power of time. Non-dispersive Cosine-Gauss wave packets and self-similar Hermite-Gauss wave packets, also well known in the field of optics and quantum mechanics, were recently studied using surface gravity waves as well. These wave packets demonstrated self-healing properties in water wave pulses as well, preserving their width despite being dispersive. Finally, this new approach also allows to observe diffractive focusing from a temporal slit with finite width.

A depth-resolved framework for the coupling of sub-surface flows and surface gravity water waves

2020 ◽  
Author(s):  
Simen Ådnøy Ellingsen ◽  
Stefan Weichert ◽  
Yan Li
Keyword(s):  
Surface Waves ◽  
Water Waves ◽  
Multiple Scales ◽  
Subsurface Flow ◽  
Vertical Gradient ◽  
Finite Depth ◽  
Surface Gravity ◽  
Linear Wave ◽  
Flow Equations ◽  
Direct Integration Method

<p>This work aims to develop a new framework for the interaction of a subsurface flow and surface gravity water waves, based on a perturbation and multiple-scales expansion.  Surface waves are assumed of a narrow band δ (δ ), indicating they can be expressed as a carrier wave whose amplitude varies slowly in space and time relative to its phase. Using the Direct Integration Method proposed in Li & Ellingsen (2019), the effects of the vertical gradient of a subsurface flow are taken into account on the linear wave properties in an implicit fashion. At the second order in wave steepness ϵ, the forcing of the sub-harmonic bound waves is considered that plays a role in the primary equations for a subsurface flow.</p><p>The novel framework derives the continuity and momentum equations for a subsurface flow in two different formats, including both the depth integrated as well as the depth resolved version. The former compares with Smith (2006) to examine the roles of the rotationality of wave motions in the subsurface flow equations. The latter employs the sigma coordinate system proposed in Mellor (2003, 2008, 2015) and extends the framework therein to allow for quasi-monochromatic surface waves and the effects of the shear of a current on linear surface waves. Compared to Mellor (2003, 2008, 2015), the vertical flux/vertical radiation stress term in the proposed framework is approximated to one order of magnitude higher, i.e. O(ϵ<sup>2</sup>δ<sup>2</sup>).</p><p><strong>References</strong></p><p>Li, Y., Ellingsen, S. Å. A framework for modeling linear surface waves on shear currents in slowly varying waters. J. Geophys. Res. C: Oceans, (2019) <strong>124</strong>(4), 2527-2545.</p><p>Mellor, G. L. The three-dimensional current and surface wave equations. J. Phys. Oceanogr., (2003) <strong>33</strong>, 1978–1989.</p><p>Mellor, G. L. The depth-dependent current and wave interaction equations: a revision. J. Phys. Oceanogr., (2008) <strong>38</strong>(11), 2587-2596.</p><p>Smith, J. A. Wave–current interactions in finite depth. Journal of Physical Oceanography, (2006) <strong>36</strong>(7), 1403-1419.</p>

scholarly journals Experimental study of spatiotemporally localized surface gravity water waves

2012 ◽  
Vol 86 (1) ◽  
Author(s):  
A. Chabchoub ◽  
N. Akhmediev ◽  
N. P. Hoffmann
Keyword(s):  
Experimental Study ◽  
Water Waves ◽  
Surface Gravity

scholarly journals Experimental study of particle trajectories below deep-water surface gravity wave groups

2019 ◽  
Vol 879 ◽  
pp. 168-186 ◽  
Author(s):  
T. S. van den Bremer ◽  
C. Whittaker ◽  
R. Calvert ◽  
A. Raby ◽  
P. H. Taylor
Keyword(s):  
Gravity Wave ◽  
Deep Water ◽  
Water Waves ◽  
Wave Equations ◽  
Stokes Drift ◽  
Surface Gravity ◽  
Return Flow ◽  
Surface Gravity Wave ◽  
Wave Groups ◽  
Wave Induced

Owing to the interplay between the forward Stokes drift and the backward wave-induced Eulerian return flow, Lagrangian particles underneath surface gravity wave groups can follow different trajectories depending on their initial depth below the surface. The motion of particles near the free surface is dominated by the waves and their Stokes drift, whereas particles at large depths follow horseshoe-shaped trajectories dominated by the Eulerian return flow. For unidirectional wave groups, a small net displacement in the direction of travel of the group results near the surface, and is accompanied by a net particle displacement in the opposite direction at depth. For deep-water waves, we study these trajectories experimentally by means of particle tracking velocimetry in a two-dimensional flume. In doing so, we provide visual illustration of Lagrangian trajectories under groups, including the contributions of both the Stokes drift and the Eulerian return flow to both the horizontal and the vertical Lagrangian displacements. We compare our experimental results to leading-order solutions of the irrotational water wave equations, finding good agreement.

Wave Motion Control Over Submerged Horizontal Plates

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
D. Karmakar ◽  
C. Guedes Soares
Keyword(s):  
Gravity Waves ◽  
Incident Wave ◽  
Water Waves ◽  
Wave Motion ◽  
Offshore Structures ◽  
Surface Gravity ◽  
Wave Transformation ◽  
Angle Of Incidence ◽  
Surface Gravity Waves ◽  
Submerged Plate

The interaction of surface gravity waves with horizontal pitching plate for actively control waves is investigated based on the linearized theory of water waves. The three-dimensional (3D) problem is formulated for the submerged plate pitching about its middle point and the other plate is considered to be floating above the submerged plate. The submerged plate's thickness is considered negligible in comparison with the water depth and wavelength of the incident wave. The study is carried out using the matched eigenfunction expansion method and the analytical solution is developed for the interaction of the surface gravity waves with horizontal submerged structure. The performance is analyzed for both impermeable and porous submerged pitching plate. The numerical results for the reflection coefficient, transmission coefficient, and free-surface deflection are computed and analyzed. The study is carried to find the optimal value of the length and depth of the submerged plate at which the dissipation of the incident wave energy is observed. The reduction the wave transformation due to the pitching of the plate with the change in angle of incidence is also analyzed. The present study will be helpful in the analysis of proper functioning of submerged pitching plate to control wave motion for the protection of offshore structures.

scholarly journals A Unified Breaking Onset Criterion for Surface Gravity Water Waves in Arbitrary Depth

2020 ◽  
Vol 125 (7) ◽  
Author(s):  
Morteza Derakhti ◽  
James T. Kirby ◽  
Michael L. Banner ◽  
Stephan T. Grilli ◽  
Jim Thomson
Keyword(s):  
Water Waves ◽  
Surface Gravity

Wave Motion Control Over Submerged Horizontal Plates

2015 ◽  
Author(s):  
D. Karmakar ◽  
C. Guedes Soares
Keyword(s):  
Gravity Waves ◽  
Incident Wave ◽  
Water Waves ◽  
Wave Motion ◽  
Offshore Structures ◽  
Surface Gravity ◽  
Wave Transformation ◽  
Angle Of Incidence ◽  
Surface Gravity Waves ◽  
Submerged Plate

The interaction of surface gravity waves with horizontal pitching plate for actively control waves is investigated based on the linearized theory of water waves. The two dimensional problem is formulated for the submerged plate pitching about its middle point and the other plate is considered to be floating above the submerged plate. The submerged plate’s thickness is considered negligible in comparison with the water depth and wavelength of the incident wave. The study is carried out using the matched eigenfunction expansion method and the analytical solution is developed for the interaction of the surface gravity waves with horizontal submerged structure. The numerical results for the reflection coefficient, transmission coefficient and free surface deflection are computed and analyzed. The study is carried to find the optimal value of the length and depth of the submerged plate at which the dissipation of the incident wave energy is observed. The reduction the wave transformation due to the pitching of the plate with the change in angle of incidence is also analyzed. The present study will be helpful in the analysis of proper functioning of submerged pitching plate to control wave motion for the protection of offshore structures.

Scattering of Surface Gravity Waves by Islands, Reefs, and Barriers

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Gravity Waves ◽  
Water Waves ◽  
Surface Displacement ◽  
Deep Ocean ◽  
Surface Gravity ◽  
Edge Waves ◽  
Surface Gravity Waves ◽  
Present Context ◽  
Constant Slope ◽  
Sloping Beach

This chapter focuses on the scattering of surface gravity waves by islands, reefs, and barriers. Surface gravity waves that propagate from the deep ocean to coastal regions may be strongly amplified by reflection, refraction, diffraction, and shoaling due to variation in water depth. Analytical solutions provide an attractive approach to studies on wave scattering, but they are obtainable for only special topographies and simple governing equations. The chapter considers long surface gravity waves (linear shallow water waves) such that the depth of the water is much greater than the vertical free surface displacement and the wavelength is much larger than the depth. The fluid equations are derived directly for the present context. The discussion covers trapped waves, the scattering or S-matrix, submerged circular islands, edge waves on a sloping beach, one-dimensional edge waves on a constant slope, and wave amplication by a sloping beach.

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