scholarly journals TSUNAMI GENERATION BY EARTHQUAKES: SEABED TOPOGRAPHY AND INERTIAL EFFECTS

2018 ◽  
pp. 58
Author(s):  
Robert A. Dalrymple ◽  
Morteza Derakhti
Keyword(s):  
Gravity Waves ◽  
Acoustic Waves ◽  
Smooth Particle Hydrodynamic ◽  
Far Field ◽  
Relative Importance ◽  
Inertial Effects ◽  
Tsunami Generation ◽  
Moving Bed ◽  
Surface Gravity Waves ◽  
Seabed Topography

In this presentation, we examine the effects of the shape and height of a moving bed on the generated surface gravity waves using the 3-D Smooth Particle Hydrodynamic model, GPUSPH (Hérault et al., 2010). Further, we investigate the relative importance of the inertial effects on the general characteristics of the generated Tsunami in the near- and far-field for various rates of the bed displacement, ranging from creeping to impulsive regimes. The sensitivity of the inertial effects on the shape of the moving bed is also discussed. Finally, the characteristics of the acoustic waves generated during the various bed displacement scenarios are examined.

scholarly journals TOMOGRAPHY OF THE SOLAR INTERIOR

2006 ◽  
Vol 21 (22) ◽  
pp. 1701-1715 ◽  
Author(s):  
L. GIZON
Keyword(s):  
Gravity Waves ◽  
Acoustic Waves ◽  
Solar Surface ◽  
Three Dimensional ◽  
Magnetic Activity ◽  
Solar Interior ◽  
Turbulent Convection ◽  
Convective Structures ◽  
Surface Gravity Waves ◽  
Rich Spectrum

Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision Doppler images of the solar surface. The purpose of helioseismology is to retrieve information about the structure and the dynamics of the solar interior from the frequencies, phases and amplitudes of solar waves. Methods of analysis are being developed to make three-dimensional images of subsurface motions and temperature inhomogeneities in order to study convective structures and regions of magnetic activity, like sunspots.

Acoustic radiation by ocean surface waves

2000 ◽  
Vol 415 ◽  
pp. 1-21 ◽  
Author(s):  
STEVE ARENDT ◽  
DAVID C. FRITTS
Keyword(s):  
Surface Waves ◽  
Gravity Waves ◽  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Three Dimensional ◽  
Phase Speed ◽  
Ocean Surface ◽  
Surface Gravity ◽  
Ocean Surface Waves ◽  
Surface Gravity Waves

We calculate the radiation of acoustic waves into the atmosphere by surface gravity waves on the ocean surface. We show that because of the phase speed mismatch between surface gravity waves and acoustic waves, a single surface wave radiates only evanescent acoustic waves. However, owing to nonlinear terms in the acoustic source, pairs of ocean surface waves can radiate propagating acoustic waves if the two surface waves propagate in almost equal and opposite directions. We derive an analytic expression for the acoustic radiation by a pair of ocean surface waves, and then extend the result to the case of an arbitrary spectrum of ocean surface waves. We present some examples for both the two-dimensional and three-dimensional regimes. Of particular note are the findings that the efficiency of acoustic radiation increases at higher wavenumbers, and the fact that the directionality of the acoustic radiation is often independent of the shape of the spectrum.

The radiation and scattering of surface waves by a vertical circular cylinder in a channel

1992 ◽  
Vol 338 (1650) ◽  
pp. 325-357 ◽  
Keyword(s):  
Circular Cylinder ◽  
Gravity Waves ◽  
The Body ◽  
Far Field ◽  
Algebraic Equations ◽  
Surface Gravity Waves ◽  
Infinite Systems ◽  
Linear Algebraic Equations ◽  
Correct Form ◽  
Body Boundary

In this paper we consider the problems of the radiation and scattering of surface gravity waves by a vertical circular cylinder placed on the centreline of a channel of width 2 d and depth H , and either extending from the bottom through the free surface or truncated so as to fill only part of the depth. These problems are solved, for arbitrary incident wavenumber k , by constructing appropriate multipoles for cylinders placed symmetrically in channels and then using the body boundary condition to derive a set of infinite systems of linear algebraic equations. For the general problems considered here, this method is superior to the more usual approach of using a set of image cylinders to model the channel walls, in particular the occurrence of modes other than the fundamental when kd > is accurately modelled and the correct form predicted for the far-field.

scholarly journals Effects of an abrupt depth change on weakly nonlinear surface gravity waves: deterministic and stochastic analysis

2020 ◽  
Author(s):  
Yan Li ◽  
Samuel Draycott ◽  
Yaokun Zheng ◽  
Thomas A.A. Adcock ◽  
Zhiliang Lin ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Second Order ◽  
Surface Gravity ◽  
Irregular Waves ◽  
Wave Steepness ◽  
Weakly Nonlinear ◽  
Wave Statistics ◽  
Surface Gravity Waves ◽  
Seabed Topography ◽  
Nonlinear Surface

<p>This work focuses on two different aspects of the effect of an abrupt depth transition on weakly nonlinear surface gravity waves: deterministic and stochastic. It is known that the kurtosis of waves can reach a maximum near the top of such abrupt depth transitions. The analysis is based on three different approaches: (1) a novel theoretical framework that allows for narrow-banded surface waves experiencing a step-type seabed, correct to the second order in wave steepness; (2) experimental observations; and (3) a numerical model based on a fully nonlinear potential flow solver. To reveal the fundamental physics, the evolution of a wave envelope that experiences an abrupt depth transition is examined in detail; (a) we show the release of free waves at second order in wave steepness both for the super-harmonic and sub-harmonic or ‘mean’ terms; (b) a local wave height peak that occurs near the top of a depth transition – whose exact position depends on several nondimensional parameters – is revealed; (c) furthermore, we examine which parameters affect this peak. The novel physics has implications for wave statistics for long-crested irregular waves experiencing an abrupt depth transition. We show the connection of the second-order physics at work in the deterministic and stochastic cases: the peak of wave kurtosis and skewness occurs in the neighborhood of the deterministic wave peak in (b) and for the same parameters set composed of a seabed topography, water depths, primary wave frequency and steepness, and bandwidth.</p>

scholarly journals Modeling and control of surface gravity waves in a model of a copper converter

2008 ◽  
Vol 32 (9) ◽  
pp. 1696-1710 ◽  
Author(s):  
Eduardo Godoy ◽  
Axel Osses ◽  
Jaime H. Ortega ◽  
Alvaro Valencia
Keyword(s):  
Gravity Waves ◽  
Surface Gravity ◽  
Modeling And Control ◽  
Copper Converter ◽  
Surface Gravity Waves ◽  
And Control

Irrotational, progressive surface gravity waves near the limiting height

1973 ◽  
Vol 29 (3) ◽  
pp. 94-105 ◽  
Author(s):  
Ken Sasaki ◽  
Takashi Murakami
Keyword(s):  
Gravity Waves ◽  
Surface Gravity ◽  
Surface Gravity Waves
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