The Wave Field Near a Narrow Convex Impedance Cone Completely Illuminated by a Plane Incident Wave

2019 ◽  
Vol 238 (5) ◽  
pp. 689-700
Author(s):  
M. A. Lyalinov ◽  
S. V. Polyanskaya
Keyword(s):  
Wave Field ◽  
Incident Wave ◽  
Plane Incident Wave ◽  
Impedance Cone

Wave-Vessel Interactions in Beam Seas

2009 ◽  
Author(s):  
Eirini Spentza ◽  
Chris Swan
Keyword(s):  
Wave Field ◽  
Incident Wave ◽  
Laboratory Data ◽  
Wave Structure ◽  
Wave Pattern ◽  
Scaled Model ◽  
Beam Seas ◽  
Wave Basin ◽  
Wave Slamming ◽  
Speed Of Propagation

This paper concerns the nonlinear interaction of waves with a floating vessel. A detailed experimental study has been undertaken in a 3-D wave basin, using a scaled model tanker subject to a variety of incident wave conditions. The vessel, which is free to move in heave, pitch and roll, has a draft of 14m (at full-scale) and is subject to a range of incident wave periods propagating at right angles to the side shell of the vessel. Measurements undertaken with and without the vessel in place allow the diffracted-radiated wave field to be identified. The laboratory data indicate that the diffracted-radiated wave pattern varies significantly with the incident wave period. Detailed analysis of the experimental results has identified a hitherto unexpected second-order freely propagating wave harmonic generated due to the presence of the vessel. Given its frequency content and its relatively slow speed of propagation, this harmonic leads to a significant steepening of the wave field around the vessel and therefore has an important role to play in terms of the occurrence of wave slamming. Physical insights are provided concerning the latter and the practical implications of the overall wave-structure interactions are considered.

Numerical and Experimental Investigations of Wave Field Around a Circular Island with the Presence of Weak Currents

2002 ◽  
Vol 18 (1) ◽  
pp. 35-42
Author(s):  
Ming-Chung Lin ◽  
Chao-Min Hsu ◽  
Shou-Cheng Wang ◽  
Chao-Lung Ting
Keyword(s):  
Experimental Data ◽  
Wave Field ◽  
Wave Height ◽  
Incident Wave ◽  
Numerical Calculations ◽  
Experimental Investigations ◽  
Wave Refraction ◽  
Circular Island ◽  
Incident Waves ◽  
A Current

ABSTRACTThis study elucidated the complicated phenomena of wave refraction and diffraction around a circular island due to random incident waves traveling with a current. Various combinations of random incident wave and current conditions were used to investigate the wave height distributions around a circular island numerically and experimentally. Numerical calculations were carried out based on the theory derived by Lin & Hsu [1]. According to the results, it shows that numerical calculations can predict experimental data quantitatively well.

Wave Kinematics and Seakeeping Calculation With Varying Bathymetry

2009 ◽  
Author(s):  
Guillaume de Hauteclocque ◽  
Fla´via Rezende ◽  
Yann Giorgiutti ◽  
Xiao-Bo Chen
Keyword(s):  
Boundary Element Method ◽  
Wave Field ◽  
Incident Wave ◽  
Added Mass ◽  
Radiation Damping ◽  
Floating Body ◽  
Diffraction Radiation ◽  
Constant Depth ◽  
Wave Kinematics ◽  
Radiation Theory

Diffraction/Radiation theory is used to calculate the wave kinematics and the motions of a floating body in area of varying bathymetry. The bathymetry is modeled as a second body, which, without special measures, leads to spurious reflection at the edge of the mesh. A modified formulation of the Boundary Element Method is introduced to model partially transparent panels. Those panels, when properly used to smoothly extend the actual (opaque) bathymetry, allow much more accurate computation. The efficiency of the method is tested with regards of several parameters concerning the bathymetry size and the way to smooth the truncation. Numerical results are satisfactorily compared with a 3D shallow water code based on Green-Naghdi theory. The sensitivity to the slope on the ship response is then investigated (motion, added mass, radiation damping and second order loads). The differences with the constant depth calculations are significant, due to the modified incident wave field, but also due to modified added mass and radiation damping terms. The method presented here could be useful in the context of LNG terminals where the depth is quite shallow and the bathymetric variations significant.

The Interaction of Nonlinear Waves With the Submerged Caissons of a Gravity Based Structure

2008 ◽  
Author(s):  
Marios Christou ◽  
Jannicke S. Roos ◽  
Chris Swan ◽  
Ove T. Gudmestad
Keyword(s):  
Wave Field ◽  
Incident Wave ◽  
Nonlinear Waves ◽  
Wave Structure ◽  
Boundary Integral ◽  
Numerical Predictions ◽  
Water Region ◽  
Geometric Discontinuities ◽  
The Waves ◽  
Wave Structure Interaction

This paper concerns the numerical description of nonlinear waves propagating over the storage caissons of a gravity based structure. This process produces a steepening of the incident wave-field, which occurs when the waves propagate into the shallower water region above the storage caissons, resulting in the focussing of wave energy. A fully nonlinear Multiple-flux Boundary Element Method (MF-BEM) is applied to simulate this effect. The MF-BEM differs from traditional boundary integral approaches in two important respects: first, a multiple-flux approach is employed to overcome the problem of geometric discontinuities; and, second, no filtering, smoothing, re-gridding or redistribution of the nodes is performed at any stage during the simulations. These two aspects are believed to play an important role in accurately predicting the steepening of the incident wave-field. The numerical predictions are compared to new laboratory observations that examine the extent of this wave-structure interaction and, particularly, the steepening of the incident wave-field.

scholarly journals EVALUATION FOR LOCAL SITE EFFECT OF SEDIMENTARY BASIN TAKING INTO ACCOUNT INCIDENT WAVE FIELD

1999 ◽  
pp. 13-25
Author(s):  
Kiyotaka SATO ◽  
Sadanori HIGASHI ◽  
Shunji SASAKI ◽  
Kenzo TOKI
Keyword(s):  
Wave Field ◽  
Incident Wave ◽  
Sedimentary Basin ◽  
Site Effect ◽  
Local Site Effect ◽  
Local Site

scholarly journals Graded resonator arrays for spatial frequency separation and amplification of water waves

2018 ◽  
Vol 854 ◽  
Author(s):  
Luke G. Bennetts ◽  
Malte A. Peter ◽  
Richard V. Craster
Keyword(s):  
Spatial Frequency ◽  
Incident Wave ◽  
Water Waves ◽  
Matrix Analysis ◽  
Frequency Separation ◽  
Linear Potential ◽  
Slowing Down ◽  
Line Array ◽  
Plane Incident Wave ◽  
Transfer Matrix Analysis

A structure capable of substantially amplifying water waves over a broad range of frequencies at selected locations is proposed. The structure consists of a small number of C-shaped cylinders in a line array, with the cylinder properties graded along the array. Using linear potential-flow theory, it is shown that the energy carried by a plane incident wave is amplified within specified cylinders for wavelengths comparable to the array length and for a range of incident directions. Transfer-matrix analysis is used to attribute the large amplifications to excitation of local Rayleigh–Bloch waves and gradual slowing down of their group velocity along the array.

Seismic response of three-dimensional alluvial deposit with irregularities for incident wave motion from a point source

1994 ◽  
Vol 84 (6) ◽  
pp. 1801-1814
Author(s):  
Masahiro Kawano ◽  
Satoshi Matsuda ◽  
Kozo Toyoda ◽  
Jun Yamada
Keyword(s):  
Point Source ◽  
Wave Field ◽  
Incident Wave ◽  
Wave Motion ◽  
Surface Soil ◽  
Soil Layer ◽  
Tangential Component ◽  
Focal Distance ◽  
Alluvial Deposit ◽  
Surface Displacements

Abstract The purpose of this article is to further investigate the influence of local site conditions of surface soil layers on seismic ground motion by studying the response of a semi-spherical alluvial deposit model under the more realistic type incident wave field. The incident wave field is a spherical wave radiated from a point source that is situated at the near focal distance and the far focal distance. A plane SH wavelet is also considered for comparison. A least-squares technique is applied to solve the boundary problem. The surface displacements on the alluvial deposit and in the elastic half-space are evaluated for various focal distances and source incidence angles. The numerical results indicate that there are significant differences concerning scattering and diffraction of wave motions between the two horizontal components when the semi-spherical alluvial deposit is subjected to incident wave motions from a point source. In the near field and for the component involving predominantly P and SV waves, the coupling of these waves induces a great variation in the spatial distributions, the amplitudes, and the time histories of the surface displacements compared to the tangential component, which involves mostly SH waves. The wave propagation characteristics of this component are very similar to those for a plane SH wavelet. In the far field and for the tangential component, there is not such strong coupling among waves. It is also shown that the first reflected waves at the curved boundary are deeply related to scattering and to diffraction of wave motion in a surface soil layer with irregularities and play an important role in the development of later arrivals.

Radiation and scattering of water waves by rigid bodies

1971 ◽  
Vol 46 (1) ◽  
pp. 151-164 ◽  
Author(s):  
J. L. Black ◽  
C. C. Mei ◽  
M. C. G. Bray
Keyword(s):  
Surface Waves ◽  
Incident Wave ◽  
Water Waves ◽  
Variational Formulation ◽  
Rigid Bodies ◽  
Small Oscillation ◽  
Circular Cylinders ◽  
Wave Forces ◽  
Far Field ◽  
Plane Incident Wave

Schwinger's variational formulation is applied to the radiation of surface waves due to small oscillation of bodies. By means of Haskind's theorem the wave forces on a stationary body due to a plane incident wave are found using only far-field properties. Results for horizontal rectangular and vertical circular cylinders are presented.

On the dynamic interaction between a microdefect and a main crack

1995 ◽  
Vol 448 (1934) ◽  
pp. 449-464 ◽  
Keyword(s):  
Incident Wave ◽  
Main Crack ◽  
Integral Transform ◽  
Singular Integral Equations ◽  
Building Blocks ◽  
Dynamic Interaction ◽  
Dynamic Stress Intensity Factors ◽  
Plane Incident Wave ◽  
Incident Waves ◽  
Non Destructive

A generalized theoretical approach is presented for the dynamic interaction between an arbitrarily located and oriented microdefect and a finite main crack subjected to a plane incident wave. The analysis is based upon the use of integral transform techniques and an appropriate superposition procedure. The resulting dynamic stress intensity factors ( K * I and K * II ) at the main crack are obtained by solving the appropriate singular integral equations, using Chebyshev polynomi­als, for different incident waves. The resulting solution is verified by comparison with existing results, and numerical examples are provided to show the effect of the location and orientation of the microdefect and the frequency of the incident wave upon K * I and K * II of the main crack. The results advanced here can be used as building blocks in the fields of micromechanics, damage and non-destructive characterization of defects in solids.

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