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1

Adaptive trans-dimensional inversion of multimode dispersion curve based on slime mold algorithm

Wang Xin, Feng Xuan, Liu Qian, Bai Han, Dong Xuri, Wang TaiHan

Acta Geophysica

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2024

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Vol. 72, no. 1

233-–245

EN

With the rise of low-cost and high-density observation system Distributed Acoustic Sensing (DAS), the effective utilization of high-mode surface wave becomes extremely important due to unique measuring method of DAS. To solve the interference of mode identification of dispersion curve and model dimension division on inversion results, we introduced the fitting degree of the dispersion curve, the model dimension, and the uncertainty estimation of the picked dispersion curve to construct a new objective function, and developed a strategy of adaptive trans-dimensional inversion of multimode dispersion curve based on slime mold algorithm (SMA). The research results show that our objective function can not only satisfy the fitting degree of dispersion curve, but also adaptively select the best model dimension, and does not depend on the mode identification of dispersion curve. Inversion strategy based on SMA algorithm has high flexibility, accuracy, stability, and practicality. Our method develops a new technology for dispersion curve inversion and provides a new idea for DAS system to realize low-cost and high-resolution city underground structure detection.

2

Investigation of signals of the range 10-3 - 10-4 Hz registered by water-tube tiltmeters in the underground geodynamic laboratory in Książ (SW Poland)

Kaczorowski Marek, Kasza Damian, Zdunek Ryszard, Wronowski Roman

Artificial Satellites : Journal of Planetary Geodesy

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2022

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Vol. 57, No. 4

210--236

EN

The Geodynamic Laboratory in Książ includes investigations of various kinds of geodynamic signals. Among others, we registered harmonic signals of the range 10-3 - 10-4 Hz. These signals had been found in the measurement series of the long water-tube (WT) tiltmeters. The discovered signals consist of two classes of harmonics associated with various kinds of phenomena. The first class of these signals belongs to viscoelastic vibrations of the Earth’s solid body, while the second class is produced possibly by the extremely long atmospheric infrasound waves. The signals of the vibrations of the Earth had been well recognized by the characteristic frequencies of the Earth’s free vibrations’ resonance, which occur mainly after strong earthquakes. The atmospheric pressure microvibrations affected the water level in the hydrodynamic systems of the WTs as a result of an inverse barometric effect. We observed that signals from both classes blend in the harmonics of similar frequencies and jointly affect the hydrodynamic systems of the WTs. We found that the amplitude of the secondclass signals strongly depends on the location of water-tube gauges inside the underground, while the amplitudes of the first-class signals are similar for all the gauges. These observations clearly indicate the atmospheric origin of the second class of registered signals.

3

Measurements and numerical modelling of surface waves in front of the port of split

Leder N., Duplančić Leder T., Lončar G.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2020

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Vol. 14, no. 1

191--197

EN

Wind generated surface waves were measured at V2 station (φ=43°29.3’ N; λ=16° 27.9’ E) in the Brački Kanal Channel area of the Middle Adriatic, in front of the port of Split. This was undertaken in the time interval from November 2007 to June 2008, by using Datawell MKIII waverider with all its compo-nents. For the analysis and description of extreme sea states maximum recorded wave height Hmax and sig-nificant wave height H1/3 were presented as well as associated wave spectra. The measurement results show that much larger waves appear in the open Adriatic compared to the Middle Adriatic channel area. Numerical modelling of wave generation in the Brački Kanal Channel area and wider island area of the Middle Adriatic Sea was performed by using Mike 21/SW numerical model. Wind field used for the forcing in numerical simulations relies on the results of the prognostic atmospheric model Aladin-CRO. For verification of model results, results of measurement at a waverider station V2 located in front of the port of Split were used. It was concluded that measured and modelled significant wave heights were very well matched.

4

Wave propagation in 2D between two elastic media in contact in theory of generalized two temperature thermoelasticity with gravity effect

Lotfy Khaled, Gabr Mahmoud, El-Bary Alaa Abd

Archives of Thermodynamics

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2020

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Vol. 41, no 1

219--243

EN

The theory of generalized two-temperature thermoelasticity is used to solve the boundary value problems between two elastic media with two different types of temprature under the influence of gravity.The classical dynamical coupled theory and Lord-Şhulman theory are used to obtain the general solution of the governing equations and investigate the effect of surface waves in an isotropic elastic medium subjected to gravity field. The harmonic vibrations method is used to obtain the displacement components, stress tensor and temperature distribution in the considerd physical domain with comparison with the two theories. The obtained analytic solution of the problem is applied for special cases for which the effect of two temperatures is studied. The conductive and dynamical temperatures as well as stress and strain components are shown graphically for a suitable material. Some comparisons are also introduced in the absence and in the presence of gravity, and two-temperature parameter. The differences in the obtained results between the two theories are considered.

5

Dynamics of the FKT system with different mooring lines

Wu Jo-Ti, Chen Jiahn-Horng, Hsin Ching-Yeh, Chiu Forng-Chen

Polish Maritime Research

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2019

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nr 1

20--29

EN

To harness the endless hydrokinetic energy of the Kuroshio current, the joint research team of the National Taiwan University and the National Taiwan Ocean University has developed a floating Kuroshio turbine (FKT) system in Taiwan. In normal operation, the system floats at a certain small depth from the ocean surface to reduce the wave effects and take advantage of faster current speeds. In the present study, the effect of the mooring line on the system dynamics is investigated computationally. Two different auxiliary mooring line designs and, for each design, three different common mooring lines (polyester ropes of neutral buoyancy, iron chains, and 6×19 wires ropes with wire core) are examined. The study makes use of several commercial and in-house packages, integrated to find various coefficients. It is found that the mooring line, the auxiliary mooring line design, and the gravity centre can have a significant effect on system fluctuations in normal operation if the combination of these factors is not properly matched.

6

On propagation of Rayleigh type surface wave in five different theories of thermoelasticity

Singh B., Verma S.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 3

661--673

EN

The governing equations for a homogeneous and isotropic thermoelastic medium are formulated in the context of coupled thermoelasticity, Lord and Shulman theory of generalized thermoelasticity with one relaxation time, Green and Lindsay theory of generalized thermoelasticity with two relaxation times, Green and Nagdhi theory of thermoelasticity without energy dissipation and Chandrasekharaiah and Tzou theory of thermoelasticity. These governing equations are solved to obtain general surface wave solutions. The particular solutions in a halfspace are obtained with the help of appropriate radiation conditions. The two types of boundaries at athe surface of a half-space are considered namely, the stress free thermally insulated boundary and stress free isothermal boundary. The particular solutions obtained in a half-space satisfy the relevant boundary conditions at the free surface of the half-space and a frequency equation for the Rayleigh wave speed is obtained for both thermally insulated and isothermal cases. The non-dimensional Rayleigh wave speed is computed for aluminium metal to observe the effects of frequency, thermal relaxation time and different theories of thermoelasticity.

7

Flow-induced Vibrations of a Horizontal Elastic Band Plate Submerged in Fluid of Finite Depth

Szmidt Kazimierz, Hedzielski Benedykt

Archives of Hydro-Engineering and Environmental Mechanics

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2019

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Vol. 66, nr 3-4

101--130

EN

The paper deals with forced vibrations of a horizontal thin elastic plate submerged in a semi-infinite layer of fluid of constant depth. The pressure load on this plate is induced by water waves arriving at the plate. This load is accompanied by pressure resulting from the motion of the plate. The plate and fluid motions depend on boundary conditions, and, in particular, the pressure load depends on the width of the gap between the plate and the bottom. In theoretical description of the phenomenon, we deal with a coupled problem of hydrodynamics in which the plate and fluid motions are coupled through boundary conditions at the plate surfaces. The main attention is focused on transient solutions of the problem, which correspond to fluid (and plate) motion starting from rest. In formulation of this problem, a linear theory of small deflections of the plate is employed. In order to calculate the fluid pressure, a solution of Laplace’s equation is constructed in a doubly connected fluid domain. With respect to the initial value problem considered, we confine our attention to a finite fluid domain. For a finite elapse of time, measured from the starting point, the solution in the finite fluid area mimics a solution within an infinite domain, inherent for wave propagation problems. Because of the complicated structure of boundary conditions of the coupled problem considered, the fluid domain is divided into sub-domains of simple geometry, and the solutions of the problem equations are constructed separately in each of these domains. Numerical experiments have been conducted to illustrate the formulation developed in this paper.

8

Seismic crust structure beneath the Aegean region in southwest Turkey from radial anisotropic inversion of Rayleigh and Love surface waves

Çakır Ö.

Acta Geophysica

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2018

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Vol. 66, no. 6

1303--1340

EN

The Turkish plate is covered by hundreds of accelerometer and broadband seismic stations with less than 50 km inter-station distance providing high-quality earthquake recordings within the last decade. We utilize part of these stations to extract the fundamental mode Rayleigh and Love surface wave phase and group velocity data in the period range 5–20 s to determine the crust structure beneath the Aegean region in southwest Turkey. The observed surface wave signals are interpreted using both single-station and two-station techniques. A tomographic inversion technique is employed to obtain the two-dimensional group velocity maps from the single-station group velocities. One-dimensional velocity–depth profiles under each twodimensional mesh point, which are jointly interpreted to acquire the three-dimensional image of the shear-wave velocities underneath the study area, are attained by utilizing the least-squares inversion technique, which is repeated for both Rayleigh and Love surface waves. The isotropic crust structure cannot jointly invert the observed Rayleigh and Love surface waves where the radial anisotropic crust better describes the observed surface wave data. The intrusive magmatic activity related to the northward subducting African plate under the Turkish plate results the crust structure deformations, which we think, causing the observed radial anisotropy throughout complex pattern of dykes and sills. The magma flow resulting in the mineral alignment within dykes and sills contributes to the observed anisotropy. Due to the existence of dykes, the radial anisotropy in the upper crust is generally negative, i.e., vertically polarized S-waves (Vsv) are faster than horizontally polarized S-waves (Vsh). Due to the existence of sills, the radial anisotropy in the middle-to-lower crust is generally positive, i.e., horizontally polarized S-waves (Vsh) are faster than vertically polarized S-waves (Vsv). Similar radial anisotropic results to those of the single-station analyses are obtained by the two-station analyses utilizing the cross-correlograms. The widespread volcanic and plutonic rocks in the region are consistent with the current seismic interpretations of the crustal deformations.

9

Geological and seismic investigation of former lignite mining area in Zielona Góra – two case studies

Gontaszewska-Piekarz A., Kłosiński J.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2017

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z. 64, nr 2/I

311--326

EN

The article presents two case studies of investigation carried out on plots of land, intended for multi-family residential development, lying on a former lignite mining area in Zielona Gora. It was underground mining, operating in the years 1840- 1948. Lignite deposits were extracted with the room and pillar method, i.e. with an overlayer collapse, causing deformations on the surface of the ground. In the first case study, there was no detailed mining data. In order to identify the geological structure under the planned seven-floor multi-family building, seismic surveys were performed with the technique of multichannel analysis of surface waves (MASW). Three seismic profiles were performed. They revealed the presence of several zones where S-waves had smaller velocity values. In order to verify whether the zones with the smaller values of velocity correspond to e.g. lower soil density resulting from collapsed exploitation room, some drillings were undertaken to the depth indicated in geophysical investigation. Additionally, the CPT and dynamic probing were also performed. The data obtained allowed to determine the soil parameters necessary for the safe design and foundation of the building. In the second case study, a historical mining map with the marked location of the shaft and the main galleries was used. Formerly, geological and engineering documentation for construction works had been prepared, based on 30-meter drillings and soundings with a heavy probe. The mining maps and the contemporary maps were mapped one on another carefully and accurately, calibrated with historic buildings. Thus, the accuracy of 5 m was obtained. Additionally, investigation with the MASW technique was performed. Ten seismic profiles were performed, and then verified by drillings. Also, dynamic probing in the vicinity of the expected location of the shaft was performed. Neither the MASW investigation nor the dynamic probing did not reveal any alterations in the soil condition, which would suggest the presence of the properly liquidated shaft. Thus, based exclusively on the cartographic material, the area comprising the liquidated and backfilled shaft was established. The area was excluded from the plans for the intended building erection.

PL

Artykuł przedstawia badania, jakie przeprowadzono na dwóch przykładowych działkach przeznaczonych dla zabudowy wielorodzinnej leżących na terenie dawnego górnictwa węgla brunatnego w Zielonej Górze. Było to górnictwo podziemne, działające w latach 1840-1948. Węgiel 326 A. Gontaszewska-Piekarz, J. Kłosiński brunatny eksploatowany był metodą filarowo – komorową, na zawał, powodując powstawania na powierzchni deformacji terenu. Dla niektórych fragmentów miasta zachowały się mapy górnicze. W pierwszym przypadku brak było szczegółowych danych górniczych. W celu rozpoznania budowy geologicznej pod projektowany budynek wielorodzinny, 7-kondygnacyjny wykonano geofizyczne badania sejsmiczne techniką wielokanałowej analizy fal powierzchniowych MASW. Wykonano 3 profile sejsmiczne. Wykazały one kilka niewielkich stref cechujących się niższymi wartościami prędkości fal sejsmicznych poprzecznych S. W celu weryfikacji, czy strefy obniżeń prędkości związane są np. z obniżonym zagęszczeniem gruntu wskutek zawału stropu nad komorami eksploatacyjnymi wykonano odwierty do głębokości wskazanej badaniami geofizycznymi. Wykonano także sondowania sondą CPTu oraz sondowania dynamiczne. Uzyskane dane pozwoliły na określenie parametrów podłoża koniecznych do bezpiecznego zaprojektowania posadowienia budynku. W drugim przypadku dostępna była mapa górnicza z lokalizacją szybu oraz głównych chodników.

10

Diffraction of sound pulses on a spherical target in an oceanic waveguide covered with ice

Grigorieva N., Kupriyanov M., Ostrovskiy D., Stepanova D.

Hydroacoustics

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2016

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Vol. 19

139--144

EN

This paper is devoted to modeling of the pulse scattering by a spherical target immersed in a homogeneous waveguide covered with ice. For calculating the echo signal in the frequency domain we have followed Hackman and Sammelmann’s general approach. The arising scattering coefficients of a sphere were evaluated with the use of the normal mode method. The amount of normal modes forming the backscattered field is determined by the given directivity of the source. The emitted signal is a pulse with a Gaussian envelope. Computational results are obtained in a wide frequency range 8 - 12 kHz for water depths equal to several hundreds of m, and distances between the source/receiver and a target from 1 km up to 10 km. The target is assumed to be acoustically rigid or fluid. In particular, the properties of the ice cover and a scatterer may coincide.

11

Application of Multichannel Analysis of Surface Waves to S-Phase Wave Anisotropy Estimation

Stan-Kłeczek I., Mendecki M. J.

Acta Geophysica

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2016

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Vol. 64, no. 5

1593--1604

EN

The Multichannel Analysis of Surface Waves (MASW) is an increasingly used technique for recognition of a shallow geological structure and estimation of geotechnical parameters, e.g., S-wave velocity, layer density, layer thickness, shear modulus, estimated P-wave velocity, and estimated Poisson ratio. MASW surveys were carried out in two limestone quarries in the southern part of Poland. The experimental areas are characterised by a simple geological structure: consolidated Triassic limestone. Measurement profiles were arranged as a shapely six-pointed star. For each survey line, 12 geophones with 2-meter (Deposit 1) and 3-meter (Deposit 2) spacing were applied. The research allowed to compare P- and S-wave velocity changes with the main crack systems in the studied rock masses.

12

Shallow Water Turbulent Surface Wave Striking an Adverse Slope

Bose S. K.

Acta Geophysica

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2015

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Vol. 63, no. 4

1090--1102

EN

The problem of a sinusoidal wave crest striking an adverse slope due to gradual elevation of the bed is relevant for coastal sea waves. Turbulence based RANS equations are used here under turbulence closure assumptions. Depth-averaging the equations of continuity and momentum, yield two differential equations for the surface elevation and the average forward velocity. After nondimensionalization, the two equations are converted in terms of elevation over the inclined bed and the discharge, where the latter is a function of the former satisfying a first order differential equation, while the elevation is given by a first order evolution equation which is treated by Lax-Wendroff discretization. Starting initially with a single sinusoidal crest, it is shown that as time progresses, the crest leans forwards, causing a jump in the crest upfront resulting in its roll over as a jet. Three cases show that jump becomes more prominent with increasing bed inclination.

13

Przegląd zastosowania metody interferometrii sejsmicznej

Czarny R.

Przegląd Górniczy

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2014

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T. 70, nr 7

84--91

PL

Artykuł w sposób przeglądowy przedstawia szerokie możliwości zastosowania interferometrii sejsmicznej. Metoda jest stosunkowo nowa, mając na uwadze pierwsze eksperymenty wykonane w 2001 roku, i aktualnie znajduje się w fazie dynamicznego rozwoju. W pracy omówiono jej zastosowanie w wielu zagadnieniach związanych z odwzorowaniem budowy wnętrza Ziemi oraz warstw przypowierzchniowych, a także zagadnień geoinżynierskich z np. monitorowania czynnych osuwisk. Przedstawione przykłady badań zostały opublikowane w uznanych czasopismach naukowych.

EN

The aim of this paper is to review the wide range of seismic interferometry applications. Despite the fact that only 10 years have passed since the first application was implemented in seismology, seismic interferometry is currently used in many issues beginning with analysis of the Earth´s deep interior and ending with the time-laps velocity changes at active landslides. The presented research results were published in leading scientific journals.

14

Surface wave generation due to glacier calving

Massel S.R., Przyborska A.

Oceanologia

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2013

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No. 55 (1)

101-127

EN

Coastal glaciers reach the ocean in a spectacular process called "calving". Immediately after calving, the impulsive surface waves are generated, sometimes of large height. These waves are particularly dangerous for vessels sailing close to the glacier fronts. The paper presents a theoretical model of surface wave generation due to glacier calving. To explain the wave generation process, four case studies of ice blocks falling into water are discussed: a cylindrical ice block of small thickness impacting on water, an ice column sliding into water without impact, a large ice block falling on to water with a pressure impulse, and an ice column becoming detached from the glacier wall and falling on to the sea surface. These case studies encompass simplified, selected modes of the glacier calving, which can be treated in a theoretical way. Example calculations illustrate the predicted time series of surface elevations for each mode of glacier calving.

15

Surface waves in non-homogeneous, general magnetothermo, viscoelastic media of higher order

Sethi M., Gupta K. C., Rani M.

International Journal of Applied Mechanics and Engineering

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2013

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Vol. 18, no. 4

1221--1236

EN

The aim of the present paper is to investigate surface waves in a non-homogeneous, isotropic, visco-elastic solid medium of n-th order including the time rate of strain. The theory of generalised surface waves has firstly been developed and then it has been employed to investigate particular cases of waves, viz., Stoneley, Rayleigh and Love type. The wave velocity equations have been obtained for different cases and are in well agreement with the corresponding classical result, when the effects of viscosity, temperature, magnetism as well as nonhomogeneity of the material medium are ignored.

16

Surface waves in fibre-reinforced anisotropic solid elastic media under the influence of gravity

Sethi M., Gupta K. C., Gupta D., Manisha

International Journal of Applied Mechanics and Engineering

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2013

|

Vol. 18, no. 1

177--188

EN

The aim of the present paper is to investigate surface waves in an anisotropic, elastic solid medium under the influence of gravity. First, a theory of generalised surface waves was developed and then it was employed to investigate particular cases of waves, viz., Stoneley and Rayleigh, Love type. The wave velocity equations were obtained for different cases and they are in well agreement with the corresponding classical result, when the effect of gravity, viscosity as well as parameters for fibre-reinforcement of the material medium are ignored.

17

Interaction of internal and surface waves in a two-layer fluid with free surface

Naradovy V.

Challenges of Modern Technology

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2013

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Vol. 4, no. 3

3--9

EN

The interaction of internal and surface waves in a two-layer fluid with free surface has been considered. The stability of wave packets propagation on the contact surface and free surface of hydrodynamic system „layer with rigid bottom - layer with free surface” was investigated. The amplitudes of the second harmonics of the elevations of the contact surface and the free surface are investigated.

18

Obraz falowy w miastach

Krynicki T., Kowalczyk S., Mieszkowski R., Wojas A.

Przegląd Geologiczny

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2010

|

Vol. 58, nr 5

401-407

EN

The paper presents analysis of factors influencing intensity of surface waves recorded in urban areas and methodology worked out for their measurement. Several examples of records of surface waves induced by different sources of vibrations are presented. The results of measurements show omnipresence of such waves. The wave record was executed using three-component geophones. The results of measurements show that induced vibrations may represent some hazard for buildings situated in distance up to 150 metres from their source.

19

Comparing guided modal properties of surface waves along single- and double-negative indexed slab waveguides

Kim K. Y., Cho Y. K.

Opto-Electronics Review

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2010

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Vol. 18, No. 4

388-393

EN

The guided dispersion characteristics of the fundamental symmetric and asymmetric modes of surface waves along single- and double-negative indexed slab waveguides are investigated, and a comparative analysis made when varying the single- and double-negative permittivity and permeability. While the values of the permittivity and permeability of the slab region are varied to obtain a salient picture of the guided dispersion characteristics, identical absolute product values are used for both slab cases to facilitate a reasonable comparison. In particular, in common ranges where guided mode solutions coexist for both the single- and double-negative indexed slabs, the guided mode characteristics are similar with a lower normalized frequency regime, indicating that the sign of the material parameters has a negligible effect, whereas the characteristics become quite different as the normalized frequency increases. Some other anomalous guided dispersion properties are also discussed and compared with previously reported results.

20

Surface waves in deep and shallow waters

Massel S.R.

Oceanologia

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2010

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No. 52 (1)

5-52

EN

The motion of water due to surface waves is the most dynamic factor observed in the marine environment. In this review various aspects of the wave modelling of non-linear, steep surface waves and their role in the atmosphere-ocean interaction are discussed. Significant improvements in wave forecasting have been made in the last ten years. This is to a large extent related to substantial progress in the description of wind forcing and other processes, as well as to the more efficient use of satellite observations and assimilation methods. One striking observation is the increasing variety and complexity of models in which more physical processes are implemented, greater precision and resolution achieved and extended ranges of applicability demonstrated. However in order to evaluate the applicability of particular models, comparison with high quality experimental data, collected in nature or under laboratory conditions, is necessary.