The generation of surface waves over a sloping beach by an oscillating line-source. II. The existence of wave-free source positions

1974 ◽  
Vol 76 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Clare A. N. Morris
Keyword(s):  
Surface Waves ◽  
Line Source ◽  
Sloping Beach ◽  
The Waves

AbstractAn expression is obtained for the amplitude of the waves radiated to infinity by a line source of sinusoidally-varying strength situated in water over a beach of angle α (0 < α ≤ π). It is shown that, for certain positions of the source, this amplitude is zero. Equations for the loci of these positions, and approximations to their solutions in particular cases, are derived.

Trapping modes in the theory of surface waves

1951 ◽  
Vol 47 (2) ◽  
pp. 347-358 ◽  
Author(s):  
F. Ursell
Keyword(s):  
Free Surface ◽  
Circular Cylinder ◽  
Total Energy ◽  
Surface Waves ◽  
Radiation Condition ◽  
Finite Width ◽  
Energy Trapping ◽  
Sloping Beach ◽  
The Waves

ABSTRACTIt is shown that a mass of fluid bounded by fixed surfaces and by a free surface of infinite extent may be capable of vibrating under gravity in a mode (called a trapping mode) containing finite total energy. Trapping modes appear to be peculiar to the theory of surface waves; it is known that there are no trapping modes in the theory of sound. Two trapping modes are constructed: (1) a mode on a sloping beach in a semi-infinite canal of finite width, (2) a mode near a submerged circular cylinder in an infinite canal of finite width. The existence of trapping modes shows that in general a radiation condition for the waves at infinity is insufficient for uniqueness.

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.

The generation of surface waves over a sloping beach by an oscillating line-source. I. The general solution

1974 ◽  
Vol 76 (3) ◽  
pp. 545-554 ◽  
Author(s):  
Clare A. N. Morris
Keyword(s):  
General Solution ◽  
Integral Representation ◽  
Surface Waves ◽  
Line Source ◽  
Wave Train ◽  
Wave Generation ◽  
Outgoing Wave ◽  
Arbitrary Angle ◽  
Laplace Integral Representation ◽  
Sloping Beach

AbstractThe problem of wave generation by a line source of sinusoidally varying strength situated in water above a beach of arbitrary angle α(0 < α ≤ π) is solved by the use of a Laplace-integral representation of the solution. It is shown that a solution can be constructed which is regular at the shoreline and gives an outgoing wave-train at infinity.

Characteristics of Alaskan earthquake records at distances of 40° to 70°*

1947 ◽  
Vol 37 (3) ◽  
pp. 181-195
Author(s):  
William A. Lynch ◽  
Vincent Dillon
Keyword(s):  
Surface Waves ◽  
Earthquake Records ◽  
Dominant Period ◽  
The Waves

abstract One hundred and twenty-four Alaskan and Aleutian earthquakes have been recorded at Fordham in the years 1928-1944. The Galitzin-Wilip three-component seismograph recorded 84 of these well enough to supply a basis for the present study. All epicenters lie at about the same azimuth with respect to Fordham, between 311° and 325°, and at distances of from 40° to 70°; the waves reaching Fordham therefore traveled over much the same continental paths. P was often late in terms of Macelwane's tables; emergences and impulses were almost equal in number, the former predominating slightly; often, an emergence was soon followed by a sharp impulse. S was usually sharp on both horizontals. No evidence of False S was found. Reflected phases were not prominent in the records, PR1 being recorded on only about 20 per cent of them, SR1 on about 30 per cent. The surface waves were confused and difficult to identify; only very general conclusions can be drawn about them, the most significant being a dominant period of 13.5 seconds in the coda.

scholarly journals Propagation of Surface Waves in Asphalt Pavements Generated by Different Load Impulse of Falling Weight Deflectometer

2019 ◽  
Vol 15 (1) ◽  
pp. 29-35
Author(s):  
Jozef Komačka ◽  
IIja Březina
Keyword(s):  
Surface Waves ◽  
Travel Time ◽  
Time History ◽  
Asphalt Pavements ◽  
Load Force ◽  
Falling Weight Deflectometer ◽  
Waves Propagation ◽  
Propagation Of Waves ◽  
Falling Weight ◽  
The Waves

Abstract The propagation of waves generated by load impulse of two FWD types was assessed using test outputs in the form of time history data. The calculated travel time of wave between the receiver in the centre of load and others receivers showed the contradiction with the theory as for the receivers up to 600 (900) mm from the centre of load. Therefore, data collected by the sensors positioned at the distance of 1200 and 1500 mm were used. The influence of load magnitude on the waves propagation was investigated via the different load force with approximately the same load time and vice versa. Expectations relating to the travel time of waves, depending on the differences of load impulse, were not met. The shorter travel time of waves was detected in the case of the lower frequencies. The use of load impulse magnitude as a possible explanation was not successful because opposite tendencies in travel time were noticed.

scholarly journals Mutual Interaction between Surface Waves and Langmuir Circulations Observed in Wave-Resolving Numerical Simulations

2020 ◽  
Vol 50 (8) ◽  
pp. 2323-2339
Author(s):  
Yasushi Fujiwara ◽  
Yutaka Yoshikawa
Keyword(s):  
Surface Waves ◽  
Friction Velocity ◽  
Phase Speed ◽  
Mutual Interaction ◽  
Stokes Drift ◽  
Horizontal Shear ◽  
Budget Analysis ◽  
Vorticity Budget ◽  
Langmuir Circulations ◽  
The Waves

AbstractWave-resolving simulations of monochromatic surface waves and Langmuir circulations (LCs) under an idealized condition are performed to investigate the dynamics of wave–current mutual interaction. When the Froude number (the ratio of the friction velocity of wind stress imposed at the surface and wave phase speed) is large, waves become refracted by the downwind jet associated with LCs and become amplitude modulated in the crosswind direction. In such cases, the simulations using the Craik–Leibovich (CL) equation with a prescribed horizontally uniform Stokes drift profile are found to underestimate the intensity of LCs. Vorticity budget analysis reveals that horizontal shear of Stokes drift induced by the wave modulation tilts the wind-driven vorticity to the downwind direction, intensifying the LCs that caused the waves to be modulated. Such an effect is not reproduced in the CL equation unless the Stokes drift of the waves modulated by LCs is prescribed. This intensification mechanism is similar to the CL1 mechanism in that the horizontal shear of the Stokes drift plays a key role, but it is more likely to occur because the shear in this interaction is automatically generated by the LCs whereas the shear in the CL1 mechanism is retained only when a particular phase relation between two crossing waves is kept locked for many periods.

Rayleigh surface waves along the boundary between a plasma and a metallic screen

1993 ◽  
Vol 49 (2) ◽  
pp. 227-235 ◽  
Author(s):  
S. T. Ivanov ◽  
K. M. Ivanova ◽  
E. G. Alexov
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Surface Waves ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Cyclotron Frequency ◽  
Plasma Frequency ◽  
Magnetoactive Plasma ◽  
Rayleigh Surface Waves ◽  
The Waves

Electromagnetic wave propagation along the interface between a magnetoactive plasma and a metallic screen is investigated analytically and numerically. It is shown that the waves have a Rayleigh character: they are superpositions of two partial waves. It is concluded that electromagnetic waves propagate only at frequencies lower than min (ωp, ωc), where ωpis the plasma frequency and ωcis the cyclotron frequency. The field topology is found, and the physical character of the waves is discussed.

Vertex generated waves outside metallic wedges

1961 ◽  
Vol 57 (2) ◽  
pp. 393-400 ◽  
Author(s):  
W. E. Williams ◽  
L. Rosenhead
Keyword(s):  
Exact Solution ◽  
Difference Equation ◽  
Boundary Value Problem ◽  
Surface Impedance ◽  
Line Source ◽  
Complete Agreement ◽  
Magnetic Line ◽  
Arbitrary Angle ◽  
Surface Reactance ◽  
The Waves

ABSTRACTA study is made of the waves generated by a magnetic line source placed at the vertex of a wedge of high conductivity and arbitrary angle. The boundary-value problem is reduced to the solution of a difference equation and an exact solution obtained. The method is also applied to the case of dielectric coated wedges where the surface reactance and resistance are arbitrary, and the propagation of surface waves along such surfaces is considered briefly. The forms of the solution for large and small values of the surface impedance are obtained and show complete agreement with the known results available for a right-angled wedge and a plane.

QUADRATIC NONLINEAR SURFACE WAVES

1996 ◽  
Vol 05 (01) ◽  
pp. 133-138 ◽  
Author(s):  
H.T. TRAN
Keyword(s):  
Surface Waves ◽  
Guided Waves ◽  
Quadratic Nonlinearity ◽  
Dispersion Stability ◽  
Phase Matching ◽  
Linear Medium ◽  
Nonlinear Surface Waves ◽  
Nonlinear Surface ◽  
The Waves

Nonlinear surface waves at an interface between a linear medium and another medium with quadratic nonlinearity are possible due to the phenomenon of nonlinearity-induced phase matching. The waves are numerically calculated, along with their dispersion, stability, and comparison with their cubic counterparts. An extension to guided waves is also discussed.

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