Tesi: "Ocean Wave"

1

Zhu, Qiang 1970. "Features of nonlinear wave-wave and wave-body interactions". Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/8853.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2000.
Includes bibliographical references (leaves 295-302).
Although nonlinear water waves have been the subject of decades of research, there are many problems that remain unsolved, especially in the cases when one or more of the following factors are involved: high-order nonlinear effects, moving boundaries, wavestructure interactions and complicated geometries. In this dissertation, a high-order spectral-element (HOSE) method is developed to investigate problems about nonlinear waves. An exponentially converging algorithm, it is able to be applied to solve nonlinear interactions between waves and submerged or surface-piercing bodies with high-order nonlinear effects. The HOSE method is applied to investigate dynamics of nonlinear waves and their interactions with obstacles. We first implement it to calculate the hydrodynamic forces and moments on a fixed underwater spheroid, with uniform current, different angles of attack and finite water depth included in the study. Extending this study to wave interaction with tethered bodies, we create an efficient simulation capability of moored buoys. Coupling the HOSE method with a robust implicit finite-difference solver of highly-extensible cables, our results show chaotic buoy motions and the ability for short wave generation. We then focus our attention on the free-surface patterns caused by nonlinear wave-wave and wave-body interactions. Starting with a two-dimensional canonical problem about the wave diffraction and radiation of a submerged circular cylinder, numerical evidences are obtained to corroborate that, for a fixed cylinder, a cylinder undergoing forced circular motion, or free to respond to incident waves, the progressive disturbances are in one direction only. The three-dimensional wave-wave interactions are studied. It is proved both analytically and numerically that new propagating waves could be generated by the resonant interactions between Kelvin ship waves and ambient waves. Another consequence of resonant wave-wave interactions is the instability of free-surface waves. In this dissertation, the three-dimensional unstable modes of plane standing waves and standing waves in a circular basin are identified numerically and then confirmed analytically. These investigations cover a large variety of nonlinear-wave problems and prove that the HOSE method is an efficient tool in studying scientific or practical problems.
by Qiang Zhu.
Ph.D.

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2

Naciri, Mamoun. "On wave-wave interactions on the ocean surface". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/47312.

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3

Yu, Sihan. "Ocean Wave Simulation and Prediction". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/84992.

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WiFi can provide network coverage for users on land at anytime and anywhere, but on the sea, the wireless communication scenes change dramatically due to the signals are non-existence. Although some techniques (e.g. satellite, undersea fiber, microwave communication) have been used in marine communication, they are either too expensive with very small bandwidth, or too limited in its coverage range. We propose to develop a marine wireless mesh network which is formed by low cost buoyed wireless base stations to provide broadband connectivity for users on the sea. Ocean wave simulation and prediction are key technologies in developing marine mesh network, because marine environments are dramatically different from terrestrial environment. The ocean waves have characteristics of rhythmic oscillations and the line of sight between two communication nodes is often blocked by them. Therefore, we have to develop a new wave-state-aware networking protocol which is suitable for marine environments. Ocean wave simulation technology can simulate this kind of dynamic environments and provide a test platform for the development of marine mesh network. Ocean wave prediction technology can improve the throughput of marine wireless network. Thus, they are indispensable technologies in developing marine mesh network. In this thesis, we designed an ocean wave measurement method, two ocean wave prediction methods, and an ocean wave simulation method. Firstly, we designed an accelerometer-based ocean wave measurement method. It can measure the real time wave height accurately. Secondly, we designed an Elman-neural-network-based ocean wave prediction method for nonlinear waves. It has a higher prediction accuracy than other neural network methods in nonlinear wave prediction. Thirdly, we designed a multiple-linear-regression-based ocean wave prediction method for linear waves. It has a higher prediction accuracy and less time consumption than other methods in linear wave prediction. Finally, we implemented and improved a spectrum-based ocean wave simulation method which is originally proposed by Tessendorf. It can present the movement of ocean waves realistically and in real time. To sum up, above four methods provide an effective test platform and technical support for the development of our marine mesh network.
Master of Science

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4

Greenwood, Charles. "The impact of large scale wave energy converter farms on the regional wave climate". Thesis, University of the Highlands and Islands, 2016. https://pure.uhi.ac.uk/portal/en/studentthesis/the-impact-of-large-scale-wave-energy-converter-farms-on-the-regional-wave-climate(e734db00-2108-48f9-b162-a1fc85ef61d6).html.

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5

Scott, Nicholas Vicente. "Observations of the wind-wave spectrum and steep wave statistics in open ocean waters". View online ; access limited to URI, 2003. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3103724.

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6

Suoja, Nicole Marie. "Development of a directional wave gage for short sea waves". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38163.

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7

Henry, Legena Albertha. "A study of ocean wave statistical properties using nonlinear, directional, phase-resolved ocean wave-field simulations". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1912/3230.

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Thesis (S.M.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), February 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 327-334).
In the present work, we study the statistics of wavefields obtained from non-linear phase-resolved simulations. The numerical model used to generate the waves models wave-wave interactions based on the fully non-linear Zakharov equations. We vary the simulated wavefield's input spectral properties: directional spreading function, Phillips parameter and peak shape parameter. We then investigate the relationships between a wavefield's input spectral properties and its output physical properties via statistical analysis. We investigate surface elevation distribution, wave definition methods in a nonlinear wavefield with a two-dimensional wavenumber, defined waves' distributions, and the occurrence and spacing of large wave events.
by Legena Albertha Henry.
S.M.

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8

Xue, Ming 1967. "Three-dimensional fully-nonlinear simulations of waves and wave body interactions". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10216.

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9

Proehl, Jeffrey A. "Equatorial wave-mean flow interaction : the long Rossby waves /". Thesis, Connect to this title online; UW restricted, 1988. http://hdl.handle.net/1773/10960.

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10

Guo, Y. P. "Wave-induced sound in the ocean". Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384781.

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11

Rahm, Magnus. "Ocean Wave Energy : Underwater Substation System for Wave Energy Converters". Doctoral thesis, Uppsala universitet, Elektricitetslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-112915.

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This thesis deals with a system for operation of directly driven offshore wave energy converters. The work that has been carried out includes laboratory testing of a permanent magnet linear generator, wave energy converter mechanical design and offshore testing, and finally design, implementation, and offshore testing of an underwater collector substation. Long-term testing of a single point absorber, which was installed in March 2006, has been performed in real ocean waves in linear and in non-linear damping mode. The two different damping modes were realized by, first, a resistive load, and second, a rectifier with voltage smoothing capacitors and a resistive load in the DC-link. The loads are placed on land about 2 km east of the Lysekil wave energy research site, where the offshore experiments have been conducted. In the spring of 2009, another two wave energy converter prototypes were installed. Records of array operation were taken with two and three devices in the array. With two units, non-linear damping was used, and with three units, linear damping was employed. The point absorbers in the array are connected to the underwater substation, which is based on a 3 m3 pressure vessel standing on the seabed. In the substation, rectification of the frequency and amplitude modulated voltages from the linear generators is made. The DC voltage is smoothened by capacitors and inverted to 50 Hz electrical frequency, transformed and finally transmitted to the on-shore measuring station. Results show that the absorption is heavily dependent on the damping. It has also been shown that by increasing the damping, the standard deviation of electrical power can be reduced. The standard deviation of electrical power is reduced by array operation compared to single unit operation. Ongoing and future work include the construction and installation of a second underwater substation, which will connect the first substation and seven new WECs.

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12

Semedo, Alvaro. "Atmosphere-ocean Interactions in Swell Dominated Wave Fields". Doctoral thesis, Uppsala universitet, Geovetenskapliga sektionen, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-130650.

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Ocean wind waves represent the atmosphere-ocean boundary, playing a central role in the air-sea exchanging processes. Heat, mass and momentum are transferred across this boundary, with waves mediating the exchange of principally the momentum between the winds and the ocean surface. During the generation process waves are called wind sea. When they leave their generation area or outrun their generating wind they are called swell. The wave field can be said to be dominated either by wind sea or swell. Depending on the wave regime the momentum and energy exchanging processes and the degree of coupling between the waves and the wind is different. During the growing process, waves act as a drag on the surface wind and the momentum flux is directed downward. When swell dominates the wave field a reverse momentum flux mechanism occurs triggered by swell waves traveling considerably faster than the surface winds. The momentum transfer is now directed from the waves to the atmosphere, and takes place because swell waves perform work on the atmosphere as part of their attenuation process. This upward momentum transfer has an impact on the lower atmosphere dynamics, and on the overall turbulence structure of the boundary layer. A detailed qualitative climatology of the global wind sea and swell fields from wave reanalysis data, is presented, revealing a very strong swell dominance of the World Ocean. The areas of larger potential impact of swell on the atmosphere, from a climatological point of view, are also studied. A model that reproduces the swell impact on the lower atmosphere dynamics, conceptually based on the energy transfer from the waves to the atmosphere, is presented – a new parameterization for the wave-induced stress is also proposed. The model results are compared with field observations. A modeling simulation, using a coupled wave-atmosphere model system, is used to study the impact of swell in a regional climate model, by using different formulations on how to introduce the wave state effect in the modeling system.
Gränsen mellan hav och atmosfär beskrivs av vågor, dessa spelar en central roll i utbytesprocesser mellan hav och atmosfär. Värme, massa och rörelsemängd överförs vid ytan och utbytet av rörelsemängd mellan vind och havsyta styrs i stor utsträckning av vågorna. Då vågor skapas kallas de för vinddrivna vågor. När vågorna sedan lämnar området där de genererats eller rör sig fortare än den vind som genererat dem kallas de dyning. Ett vågfält kan sägas vara dominerat av antingen vinddrivna vågor eller dyningsvågor. Beroende på vilken vågregim som råder så är kopplingen mellan vågor och vind olika och därmed också utbytesprocesserna för rörelsemängd och energi. Då vågorna genereras fungerar de som en bromsande kraft för vinden och impulsutbytet är nedåtriktat. När dyning dominerar vågfältet inträffar en mekanism för omvänt impulsutbyte som sätts igång av dyningsvågor som färdas avsevärt snabbare än vinden. Rörelsemängd överförs då från vågorna till atmosfären, eftersom dyningsvågorna utför arbete på atmosfären då de dämpas. Den uppåtriktade transporten av rörelsemängd har en stor effekt på dynamiken och turbulensstrukturen i lägre delen av atmosfären. En detaljerad kvalitativ klimatologi av globala vågfält (vinddrivna och dyning) från återanalysdata presenteras och visar att dyning dominerar vågfältet på världshaven. Områden där man kan förvänta sig störst effekt av dyning på atmosfären har identifierats. En konceptuellt baserad modell som reproducerar effekten av dyning på dynamiken i lägre delen av atmosfären presenteras. Modellen styrs av överföring av energi från vågor till atmosfären. I modellen föreslås även en ny parameterisering för våginducerad kraft på havsytan. Modellresultaten är utvärderade mot fältmätningar. En regional klimatmodell, med ett kopplat våg-atmosfärssystem, har använts för att studera den långtida effekten av dyning vid klimatsimulering. Olika formuleringar för beskrivningen av vågornas effekt på atmosfären har använts, beroende på om vinddrivna vågor eller dyning dominerar vågfältet.

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13

Ray, Timothy Allen. "Wave propagation over complex bathymetry". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FRay.pdf.

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Thesis (M.S. in Physical Oceanography)--Naval Postgraduate School, June 2003.
Thesis advisor(s): Thomas H.C. Herbers, Edward B. Thornton. Includes bibliographical references (p. 37). Also available online.

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14

Chen, David Joel. "Designing wave-measuring instruments". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12108.

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15

Wu, Cheng Y. (Cheng Yi) 1938. "Wave-wave interactions and the infrasonic pressure field in the ocean". Thesis, University of Auckland, 1988. http://hdl.handle.net/2292/2469.

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Building on Kibblewhite's long term investigations of the nonlinear wave-wave interactions and the infrasonic ocean noise and the microseisms these induce, this thesis further explores the physical nature of these processes. The classical description of this interaction, which takes into account only the homogeneous component of the induced field, has been extended to include the inhomogeneous component. A complete expression for the wave induced noise spectrum is established following a geometrical analysis of the dispersion relations among interacting waves. The relative importance of these two components and their directivity properties are also calculated and discussed. It is shown that while at observation points deeper than 500 meters the effects of the inhomogeneous component can be regarded as negligible, it can cause an increase of noise level of up to 40 dB in the region near the surface of the sea. Furthermore, in contrast to the nearly omni-directional distribution of the homogeneous component of the induced acoustic field, there is a tendency for the energy associated with the inhomogeneous component to focus in the wind direction. Based upon a multilayer analysis of a visco-elastic geoacoustic model, Green's functions and the spectral transfer functions relating the surface source pressure field to the underwater noise and microseism fields are derived for both near and far field cases. A 3-dimensional presentation defined on the dispersion plane (frequency and horizontal wave number) is introduced to describe the sea bottom reflection-loss and, Green's functions, and is extended to include the inhomogeneous region for the first time. The characteristics of this 3-D presentation are explained in terms of the geoacoustic parameters. The influence of the interaction of multiple seas (and swell) on the induced acoustic field are also discussed in this thesis. All these effects are considered in the calculation of the synthetic spectra of both the noise and microseism field. When compared with measured data excellent agreement is found between the theoretical and experimental results, which provides further confirmation that the nonlinear interaction is the most important source of the infrasonic ocean noise, as well as confirming the basic validity of the procedure introduced by Kibblewhite and Ewans to derive the ocean noise spectra from microseism records.

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16

Wist, Hanne Therese. "Statistical properties of successive ocean wave parameters". Doctoral thesis, Norwegian University of Science and Technology, Norwegian University of Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16.

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For random waves the free surface elevation can be described by a number of individual wave parameters. The main objective of this work has been to study the statistical properties of individual parameters in successive waves; the wave crest height, the wave height and the wave period.

In severe sea states the wave crest heights exhibit a nonlinear behavior, which must be reflected in the models. An existing marginal distribution that uses second order Stokes-type nonlinearity is transformed to a two-dimensional distribution by use of the two–dimensional Rayleigh distribution. This model only includes sum frequency effects. A two-dimensional distribution is also established by transforming a second order model including both sum and different frequency effects. Both models are based on the narrow-band assumption, and the effect of finite water depth is included. A parametric wave crest height distribution proposed by Forristall (2000) has been extended to two dimensions by transformation of the two-dimensional Weibull distribution.

Two successive wave heights are modeled by a Gaussian copula, which is referred to as the Nataf model. Results with two initial distributions for the transformation are presented, the Næss (1985) model and a two-parameter Weibull distribution, where the latter is in best agreement with data. The results are compared with existing models. The Nataf model has also been used for modeling three successive wave heights. Results show that the Nataf transformation of three successive wave heights can be approximated by a first order autoregression model. This means that the distribution of the wave height given the previous wave height is independent of the wave heights prior to the previous wave height. The simulation of successive wave heights can be done directly without simulating the time series of the complete surface elevation.

Successive wave periods are modeled with the Nataf transformation by using a two-parameter Weibull distribution and a generalized Gamma distribution as the initial distribution, where the latter is in best agreement with data. Results for the marginal and two-dimensional distributions are compared with existing models. In practical applications, it is often of interest to consider successive wave periods with corresponding wave heights exceeding a certain threshold. Results show that the distribution for successive wave periods when the corresponding wave heights exceed the root-mean-square value of the wave heights can be approximated by a multivariate Gaussian distribution. When comparing the results with data, a long time series is needed in order to obtain enough data cases. Results for three successive wave periods are also presented.

The models are compared with field data from the Draupner field and the Japan Sea, and with laboratory data from experiments at HR Wallingford. In addition, data from numerical simulations based on second order wave theory, including both sum and frequency effects, are included.

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17

Patoux, Jérôme. "Frontal wave development over the Southern Ocean /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/10067.

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18

Melo, Jose Luis Branco Seabra de. "Nonlinear parametric wave model compared with field data". Monterey, Calif. : Naval Postgraduate School, 1985. http://catalog.hathitrust.org/api/volumes/oclc/57738811.html.

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19

Walker, Daniel Anthony Guy. "Interaction of extreme ocean waves with offshore structures". Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:6858dc08-1bd4-4195-8893-1af98d5e68e3.

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With most of the world's untouched oil and gas resources offshore and the possibility that hurricanes are becoming more frequent and more intense, the risks associated with offshore oil and gas production are increasing. Therefore, there is an urgent need to improve current understanding of extreme ocean waves and their interaction with structures. This thesis is concerned with the modelling of extreme ocean waves and their diffraction by offshore structures, with the ultimate aim of proposing improved tools for guiding airgap design. The feasibility of using linear and second order diffraction solutions with a suitable incident wave field to predict extreme green water levels beneath multi-column structures is investigated. Such tools, when fully validated, could replace the need to carry out model tests during preliminary design. When contemplating airgap design it is crucially important that consideration is given to the largest waves in a sea state, the so-called freak or rogue waves. This thesis studies the nature of one specific freak wave for which field data is available, namely the Draupner New Year wave. Unique features of this wave are identified, distinguishing it from a typical large wave, and an estimate of the probability of occurrence of the wave is given. Furthermore, a design wave, called NewWave, is proposed as a good model for large ocean waves and is validated against field and experimental data. The diffraction of regular waves and NewWaves by a number of structural configurations is studied. In order to assess the validity of using diffraction solutions for the purposes of airgap design, comparisons are made with measured wave data from a programme of wave tank experiments. Wave data for a real platform configuration are examined to highlight the key issues complicating the validation of diffraction based design tools for real structures. The ability of diffraction theory to reproduce real wave measurements is discussed. The phenomenon of near-trapping is also investigated, allowing guidelines for airgap design to be established.

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20

Sweeny, Margaret E. "Breaking wave turbulence in the surf zone". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FSweeny.pdf.

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Thesis (M.S. in Applied Science (Physical Oceanography))--Naval Postgraduate School, June 2005.
Thesis Advisor(s): Timothy P. Stanton. Includes bibliographical references (p. 51). Also available online.

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21

Cohen, Jennifer Esther. "Theory of turbulent wind over fast and slow waves". Thesis, University of Cambridge, 1997. https://www.repository.cam.ac.uk/handle/1810/283717.

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22

Klepsvik, Jonny. "Nonlinear wave loads on offshore structures". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36062.

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23

Murphy, Darryl Guy. "Rossby waves in the Southern Ocean". Thesis, University of Exeter, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303178.

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24

Abdelrahman, Saad M. M. "Shore wave modulation due to infragravity waves in the nearshore zone, with applications". Monterey, Calif. : Naval Postgraduate School, 1986. http://catalog.hathitrust.org/api/volumes/oclc/57743239.html.

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25

Xu, Xu. "Nonlinear dynamics of parametric pendulum for wave energy extraction". Thesis, University of Aberdeen, 2005. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=189414.

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A new concept, extracting energy from sea waves by parametric pendulor, has been explored in this project. It is based on the conversion of vertical oscillations to rotational motion by means of a parametrically-excited pendulor, i.e. a pendulum operating in rotational mode. The main advantage of this concept lies in a direct conversion from vertical oscillations to rotations of the pendulum pivot. This thesis, firstly, reviewed a number of well established linear and nonlinear theories of sea waves and Airy’s sea wave model has been used in the modelling of the sea waves and a parametric pendulum excited by sea waves. The third or fifth order Stokes’s models can be potentially implemented in the future studies. The equation of motion obtained for a parametric pendulum excited by sea waves has the same form as for a simple parametrically-excited pendulum. Then, to deepen the fundamental understanding, an extensive theoretical analysis has been conducted on a parametrically-excited pendulum by using both numerical and analytical methods. The numerical investigations focused on the bifurcation scenarios and resonance structures, particularly, for the rotational motions. Analytical analysis of the system has been performed by applying the perturbation techniques. The approximate solutions, resonance boundary and existing boundary of rotations have been obtained with a good correspondence to numerical results. The experimental study has been carried out by exploring oscillations, rotations and chaotic motions of the pendulum.

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26

Peak, Scott Douglas. "Wave refraction over complex nearshore bathymetry". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FPeak.pdf.

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27

Harlander, Uwe, e Werner Metz. "Rossby wave propagation in a bounded ocean current". Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-213459.

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Die Ausbreitungspfade und die strukturelle Veränderung von quasi geostrophischen Rossby-Wellenpaketen werden mittels der WKB-Methode untersucht. Es wird angenommen, daß die Wellenpakete an einem in Ost-West-Richtung verlaufenden festen Rand reflektiert werden können. Die Dynamik der Rossby-Wellenpakete wird auf der ß-Ebene aber auch auf der sogenannten d-Oberfiäche - wo auch die zweite Ableitung des Coriolis-Parameters eine Rolle spielt - studiert. Es wird gezeigt, daß die Wellenpakete unter bestimmten Umständen große Entfernungen in zonaler Richtung entlang der Küste zurücklegen können und damit die Strömung weit stromab beeinflussen. Die Wellenpakete sind dabei zwischen dem reflektierenden Rand und einer Umkehrbreite gefangen im Unterschied zu freien Rossbywellen in der Atmosphäre, die zwischen zwei Umkehrbreiten gefangen werden können. Es zeigt sich, daß der d-Term keine besonders wichtige Rolle für die Ausbreitung der Rossby-Wellenpakete spielt, am wichtigsten ist er noch bei der Dynamik von Wellen mit negativer Phasengeschwindigkeit. Es wird vorgeschlagen, daß ein selektiver Rossby-Wellenleiter wie er hier diskutiert wird eine Rolle in der Dynamik des Antarktik-Zirkumpolarstromes spielt
We study the propagation and the structural change of quasi geostrophic Rossby wave packets by means of a WKB-method. Our approach involves the introduction of a rigid boundary, where the wave packets can be refiected elastically. We study Rossby wave packet dynamics at high latitudes on a modified ß-plane, where the second derivative of the Coriolis parameter with respect to latitude is taken into account (d-term). We show that under certain conditions synoptic-scale wave packets can propagate far distances along an east-west oriented \"coast\" and may affect the fiow far downstream of the source region. In contrast to free propagating Rossby wave packets ( e.g. in the atmosphere), which can be trapped between two turning latitudes, the wave packets considered here are trapped between a turning latitude and the reflecting boundary. lt turns out that the 6-term is most important for wave packets with negative phase speeds. Finally, we suggest that such a selective Rossby waveguide may play a role in the dynamics of the Antarctic Circumpolar Current

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28

Joubert, J. R. "An investigation of the wave energy resource on the South African Coast, focusing on the spatial distribution of the South West coast". Thesis, Link to the Internet, 2008. http://hdl.handle.net/10019.1/351.

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29

Storie, Eric S. "Multi-fractal analysis of SAR ocean wave imagery". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0014/MQ36849.pdf.

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30

Navarro, Moisés M. "Ocean wave data analysis using Hilbert transform techniques". Thesis, Monterey, California. Naval Postgraduate School, 1996. http://hdl.handle.net/10945/32022.

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A novel technique to determine the phase velocity of long-wavelength shoaling waves is investigated. Operationally, the technique consists of three steps. First, using the Hilbert transform of a time series, the phase of the analytic signal is determined. Second, the correlations of the phases of analytic signals between two points in space are calculated and an average time of travel of the wave fronts is obtained. Third, if directional spectra are available or can be determined from time series of large array of buoys, the angular information can be used to determine the true time of travel. The phase velocity is obtained by dividing the distance between buoys by the correlation time. Using the Hilbert transform approach, there is no explicit assumption of the relation between frequency and wavenumber of waves in the wave field, indicating that it may be applicable to arbitrary wave fields, both linear and nonlinear. Limitations of the approach are discussed.

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31

Tang, Dajun. "Acoustic wave scattering from a random ocean bottom". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13908.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, and Woods Hole Oceanographic Institution, 1991.
Includes bibliographical references (leaves 123-130).
Dajun Tang.
Ph.D.

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32

Harlander, Uwe, e Werner Metz. "Rossby wave propagation in a bounded ocean current". Wissenschaftliche Mitteilungen des Leipziger Instituts für Meteorologie ; 9 = Meteorologische Arbeiten aus Leipzig ; 3 (1998), S. 130-147, 1998. https://ul.qucosa.de/id/qucosa%3A15085.

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Die Ausbreitungspfade und die strukturelle Veränderung von quasi geostrophischen Rossby-Wellenpaketen werden mittels der WKB-Methode untersucht. Es wird angenommen, daß die Wellenpakete an einem in Ost-West-Richtung verlaufenden festen Rand reflektiert werden können. Die Dynamik der Rossby-Wellenpakete wird auf der ß-Ebene aber auch auf der sogenannten d-Oberfiäche - wo auch die zweite Ableitung des Coriolis-Parameters eine Rolle spielt - studiert. Es wird gezeigt, daß die Wellenpakete unter bestimmten Umständen große Entfernungen in zonaler Richtung entlang der Küste zurücklegen können und damit die Strömung weit stromab beeinflussen. Die Wellenpakete sind dabei zwischen dem reflektierenden Rand und einer Umkehrbreite gefangen im Unterschied zu freien Rossbywellen in der Atmosphäre, die zwischen zwei Umkehrbreiten gefangen werden können. Es zeigt sich, daß der d-Term keine besonders wichtige Rolle für die Ausbreitung der Rossby-Wellenpakete spielt, am wichtigsten ist er noch bei der Dynamik von Wellen mit negativer Phasengeschwindigkeit. Es wird vorgeschlagen, daß ein selektiver Rossby-Wellenleiter wie er hier diskutiert wird eine Rolle in der Dynamik des Antarktik-Zirkumpolarstromes spielt.
We study the propagation and the structural change of quasi geostrophic Rossby wave packets by means of a WKB-method. Our approach involves the introduction of a rigid boundary, where the wave packets can be refiected elastically. We study Rossby wave packet dynamics at high latitudes on a modified ß-plane, where the second derivative of the Coriolis parameter with respect to latitude is taken into account (d-term). We show that under certain conditions synoptic-scale wave packets can propagate far distances along an east-west oriented \"coast\" and may affect the fiow far downstream of the source region. In contrast to free propagating Rossby wave packets ( e.g. in the atmosphere), which can be trapped between two turning latitudes, the wave packets considered here are trapped between a turning latitude and the reflecting boundary. lt turns out that the 6-term is most important for wave packets with negative phase speeds. Finally, we suggest that such a selective Rossby waveguide may play a role in the dynamics of the Antarctic Circumpolar Current.

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33

Orszaghova, Jana. "Solitary waves and wave groups at the shore". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:5b168bdc-4956-4152-a303-b23a6067bf42.

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A significant proportion of the world's population and physical assets are located in low lying coastal zones. Accurate prediction of wave induced run-up and overtopping of sea defences are important in defining the extent and severity of wave action, and in assessing risk to people and property from severe storms and tsunamis. This thesis describes a one-dimensional numerical model based on the Boussinesq equations of Madsen and Sorensen (1992) and the non-linear shallow water equations. The model is suitable for simulating propagation of weakly non-linear and weakly dispersive waves from intermediate to zero depth, such that any inundation and/or overtopping caused by the incoming waves is also calculated as part of the simulation. Wave breaking is approximated by locally switching to the non-linear shallow water equations, which can model broken waves as bores. A piston paddle wavemaker is incorporated into the model for complete reproduction of laboratory experiments. A domain mapping technique is used in the vicinity of the paddle to transform a time-varying domain into a fixed domain, so that the governing equations can be more readily solved. First, various aspects of the numerical model are verified against known analytical and newly derived semi-analytical solutions. The complete model is then validated with laboratory measurements of run-up and overtopping involving solitary waves. NewWave focused wave groups, which give the expected shape of extreme wave events in a linear random sea, are used for further validation. Simulations of experiments of wave group run-up on a plane beach yield very good agreement with the measured run-up distances and free surface time series. Wave-by-wave overtopping induced by focused wave groups is also successfully simulated with the model, with satisfactory agreement between the experimental and the predicted overtopping volumes. Repeated simulations, now driven by second order paddle displacement signals, give insight into second order error waves spuriously generated by using paddle signals derived from linear theory. Separation of harmonics reveals that the long error wave is significantly affecting the wave group shape and leading to enhanced runu-up distances and overtopping volumes. An extensive parameter study is carried out using the numerical model investigating the influence on wave group run-up of linear wave amplitude at focus, linear focus location, and wave group phase at focus. For a given amplitude, both the phase and the focus location significantly affect the wave group run-up. It is also found that the peak optimised run-up increases with the wave amplitude, but wave breaking becomes an inhibiting factor for larger waves. This methodology is proposed for extreme storm wave induced run-up analysis.

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34

Whitford, Dennis James. "Wind and wave forcing of longshore currents across a barred beach". Thesis, Monterey, Calif. : Naval Postgraduate School, 1988. http://catalog.hathitrust.org/api/volumes/oclc/52803820.html.

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35

Waters, Rafael. "Energy from Ocean Waves : Full Scale Experimental Verification of a Wave Energy Converter". Doctoral thesis, Uppsala universitet, Elektricitetslära, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9404.

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A wave energy converter has been constructed and its function and operational characteristics have been thoroughly investigated and published. The wave energy converter was installed in March of 2006 approximately two kilometers off the Swedish west coast in the proximity of the town Lysekil. Since then the converter has been submerged at the research site for over two and a half years and in operation during three time periods for a total of 12 months, the latest being during five months of 2008. Throughout this time the generated electricity has been transmitted to shore and operational data has been recorded. The wave energy converter and its connected electrical system has been continually upgraded and each of the three operational periods have investigated more advanced stages in the progression toward grid connection. The wave energy system has faced the challenges of the ocean and initial results and insights have been reached, most important being that the overall wave energy concept has been verified. Experiments have shown that slowly varying power generation from ocean waves is possible. Apart from the wave energy converter, three shorter studies have been performed. A sensor was designed for measuring the air gap width of the linear generator used in the wave energy converter. The sensor consists of an etched coil, a search coil, that functions passively through induction. Theory and experiment showed good agreement. The Swedish west coast wave climate has been studied in detail. The study used eight years of wave data from 13 sites in the Skagerrak and Kattegatt, and data from a wave measurement buoy located at the wave energy research site. The study resulted in scatter diagrams, hundred year extreme wave estimations, and a mapping of the energy flux in the area. The average energy flux was found to be approximately 5.2 kW/m in the offshore Skagerrak, 2.8 kW/m in the near shore Skagerrak, and 2.4 kW/m in the Kattegat. A method for evaluating renewable energy technologies in terms of economy and engineering solutions has been investigated. The match between the technologies and the fundamental physics of renewable energy sources can be given in terms of the technology’s utilization. It is argued that engineers should strive for a high utilization if competitive technologies are to be developed.

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36

Noad, Imogen Frances. "Absorbing power from ocean waves : a mathematical approach to modelling wave energy converters". Thesis, University of Bristol, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752773.

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37

Li, Wei. "Numerical Modelling and Statistical Analysis of Ocean Wave Energy Converters and Wave Climates". Doctoral thesis, Uppsala universitet, Elektricitetslära, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-305870.

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Ocean wave energy is considered to be one of the important potential renewable energy resources for sustainable development. Various wave energy converter technologies have been proposed to harvest the energy from ocean waves. This thesis is based on the linear generator wave energy converter developed at Uppsala University. The research in this thesis focuses on the foundation optimization and the power absorption optimization of the wave energy converters and on the wave climate modelling at the Lysekil wave converter test site. The foundation optimization study of the gravity-based foundation of the linear wave energy converter is based on statistical analysis of wave climate data measured at the Lysekil test site. The 25 years return extreme significant wave height and its associated mean zero-crossing period are chosen as the maximum wave for the maximum heave and surge forces evaluation. The power absorption optimization study on the linear generator wave energy converter is based on the wave climate at the Lysekil test site. A frequency-domain simplified numerical model is used with the power take-off damping coefficient chosen as the control parameter for optimizing the power absorption. The results show a large improvement with an optimized power take-off damping coefficient adjusted to the characteristics of the wave climate at the test site. The wave climate modelling studies are based on the wave climate data measured at the Lysekil test site. A new mixed distribution method is proposed for modelling the significant wave height. This method gives impressive goodness of fit with the measured wave data. A copula method is applied to the bivariate joint distribution of the significant wave height and the wave period. The results show an excellent goodness of fit for the Gumbel model. The general applicability of the proposed mixed-distribution method and the copula method are illustrated with wave climate data from four other sites. The results confirm the good performance of the mixed-distribution and the Gumbel copula model for the modelling of significant wave height and bivariate wave climate.

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38

Boyd, Jeremy David. "Evaluation of ADCP wave measurements". Thesis, Monterey, Calif. : Naval Postgraduate School, 2006. http://bosun.nps.edu/uhtbin/hyperion.exe/06Dec%5FBoydE.pdf.

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Thesis (M.S. in Physical Oceanography)--Naval Postgraduate School, December 2006.
Thesis Advisor(s): Thomas H.C. Herbers. "December 2006." Includes bibliographical references (p. 51-52). Also available in print.

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39

Morris-Thomas, Michael. "An investigation into wave run-up on vertical surface piercing cylinders in monochromatic waves". University of Western Australia. School of Oil and Gas Engineering, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0010.

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[Formulae and special characters can only be approximated here. Please see the pdf version of the abstract for an accurate reproduction.] Wave run-up is the vertical uprush of water when an incident wave impinges on a free- surface penetrating body. For large volume offshore structures the wave run-up on the weather side of the supporting columns is particularly important for air-gap design and ultimately the avoidance of pressure impulse loads on the underside of the deck structure. This investigation focuses on the limitations of conventional wave diffraction theory, where the free-surface boundary condition is treated by a Stokes expansion, in predicting the harmonic components of the wave run-up, and the presentation of a simplified procedure for the prediction of wave run-up. The wave run-up is studied on fixed vertical cylinders in plane progressive waves. These progressive waves are of a form suitable for description by Stokes' wave theory whereby the typical energy content of a wave train consists of one fundamental harmonic and corresponding phase locked Fourier components. The choice of monochromatic waves is indicative of ocean environments for large volume structures in the diffraction regime where the assumption of potential flow theory is applicable, or more formally A/a < Ο(1) (A and a being the wave amplitude and cylinder radius respectively). One of the unique aspects of this work is the investigation of column geometry effects - in terms of square cylinders with rounded edges - on the wave run-up. The rounded edges of each cylinder are described by the dimensionless parameter rc/a which denotes the ratio of edge corner radius to half-width of a typical column with longitudinal axis perpendicular to the quiescent free-surface. An experimental campaign was undertaken where the wave run-up on a fixed column in plane progressive waves was measured with wire probes located close to the cylinder. Based on an appropriate dimensional analysis, the wave environment was represented by a parametric variation of the scattering parameter ka and wave steepness kA (where k denotes the wave number). The effect of column geometry was investigated by varying the edge corner radius ratio within the domain 0 <=rc/a <= 1, where the upper and lower bounds correspond to a circular and square shaped cylinder respectively. The water depth is assumed infinite so that the wave run-up caused purely by wave-structure interaction is examined without the additional influence of a non-decaying horizontal fluid velocity and finite depth effects on wave dispersion. The zero-, first-, second- and third-harmonics of the wave run-up are examined to determine the importance of each with regard to local wave diffraction and incident wave non-linearities. The modulus and phase of these harmonics are compared to corresponding theoretical predictions from conventional diffraction theory to second-order in wave steepness. As a result, a basis is formed for the applicability of a Stokes expansion to the free-surface boundary condition of the diffraction problem, and its limitations in terms of local wave scattering and incident wave non-linearities. An analytical approach is pursued and solved in the long wavelength regime for the interaction of a plane progressive wave with a circular cylinder in an ideal fluid. The classical Stokesian assumption of infinitesimal wave amplitude is invoked to treat the free-surface boundary condition along with an unconventional requirement that the cylinder width is assumed much smaller than the incident wavelength. This additional assumption is justified because critical wavelengths for wave run-up on a fixed cylinder are typically much larger in magnitude than the cylinder's width. In the solution, two coupled perturbation schemes, incorporating a classical Stokes expansion and cylinder slenderness expansion, are invoked and the boundary value problem solved to third-order. The formulation of the diffraction problem in this manner allows for third-harmonic diffraction effects and higher-order effects operating at the first-harmonic to be found. In general, the complete wave run-up is not well accounted for by a second-order Stokes expansion of the free-surface boundary condition and wave elevation. This is however, dependent upon the coupling of ka and kA. In particular, whilst the modulus and phase of the second-harmonic are moderately predicted, the mean set-up is not well predicted by a second-order Stokes expansion scheme. This is thought to be caused by higher than second-order non-linear effects since experimental evidence has revealed higher-order diffraction effects operating at the first-harmonic in waves of moderate to large steepness when k < < 1. These higher-order effects, operating at the first-harmonic, can be partially accounted for by the proposed long wavelength formulation. For small ka and large kA, subsequent comparisons with measured results do indeed provide a better agreement than the classical linear diffraction solution of Havelock (1940). To account for the complete wave run-up, a unique approach has been adopted where a correction is applied to a first-harmonic analytical solution. The remaining non-linear portion is accounted for by two methods. The first method is based on regression analysis in terms of ka and kA and provides an additive correction to the first-harmonic solution. The second method involves an amplification correction of the first-harmonic. This utilises Bernoulli's equation applied at the mean free-surface position where the constant of proportionality is empirically determined and is inversely proportional to ka. The experimental and numerical results suggest that the wave run-up increases as rc/a--› 0, however this is most significant for short waves and long waves of large steepness. Of the harmonic components, experimental evidence suggests that the effect of a variation in rc/a on the wave run-up is particularly significant for the first-harmonic only. Furthermore, the corner radius effect on the first-harmonic wave run-up is well predicted by numerical calculations using the boundary element method. Given this, the proposed simplified wave run-up model includes an additional geometry correction which accounts for rc/a to first-order in local wave diffraction. From a practical view point, it is the simplified model that is most useful for platform designers to predict the wave run-up on a surface piercing column. It is computationally inexpensive and the comparison of this model with measured results has proved more promising than previously proposed schemes.

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40

Alves, Jose Henrique Gomes de Mattos Mathematics UNSW. "A Saturation-Dependent Dissipation Source Function for Wind-Wave Modelling Applications". Awarded by:University of New South Wales. Mathematics, 2000. http://handle.unsw.edu.au/1959.4/17786.

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This study reports on a new formulation of the spectral dissipation source term Sds for wind-wave modelling applications. This new form of Sds features a nonlinear dependence on the local wave spectrum, expressed in terms of the azimuthally integrated saturation parameter B(k)=k^4 F(k). The basic form of this saturation-dependent Sds is based on a new framework for the onset of deep-water wave breaking due to the nonlinear modulation of wave groups. The new form of Sds is succesfully validated through numerical experiments that include exact nonlinear computations of fetch-limited wind-wave evolution and hindcasts of two-dimensional wave fields made with an operational wind-wave model. The newly-proposed form of Sds generates integral spectral parameters that agree more closely with observations when compared to other dissipation source terms used in state-of-the-art wind-wave models. It also provides more flexibility in controlling properties of the wave spectrum within the high wavenumber range. Tests using a variety of wind speeds, three commonly-used wind input source functions and two alternative full-development evolution limits further demonstrate the robustness and flexibility of the new saturation-dependent dissipation source term. Finally, improved wave hindcasts obtained with an implementation of the new form of Sds in a version of the WAM model demonstrate its potential usefulness in operational wind-wave forecasting applications.

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41

Ballard, Valerie Jean. "Experiments with a high frequency laser slope meter". Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367969.

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42

Magagna, Davide. "Oscillating water column wave pump : a wave energy converter for water delivery". Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/349009/.

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The research presented in this dissertation investigates the development and the performances of a new type of Wave Energy Converter (WEC) aimed to provide water delivery and energy storage in the form of potential energy. The Oscillating Water Column Wave Pump (OWCP) concept was proposed and tested through a series of experimental investigations supported by scientific theory. The OWCP was developed after an extensive study of the existing wave energy technology available, from which it emerged that the Oscillating Water Column (OWC) device could be further implemented for water delivery purposes. The existing theory of the OWC was employed to develop a mathematical theory able to describe the system wave response and water removal of the OWCP. In order to understand and validate the mathematical models of the OWCP, experimental investigations were carried out under the influence of incident linear waves in a two-dimensional (2D) and three-dimensional (3D) wave flume. The experimental equipment and methodology are outlined, including the description of wave flumes, models and data acquisition equipment. Experimental tests were used to verify the concept of the OWCP and assess its performances, investigating both the response of the device to the waves with and without water removal. In order to increase the efficiencies of delivery, array configurations of multiple OWCPs were adopted. The research demonstrated that up to 14% of the energy carried by the incoming waves can be converted into useful potential energy for a single device. Moreover a further increase of the efficiencies can be obtained with the array configuration improving the overall capability of the OWCP, for optimal separation distance between the array components. Further model tests are required to extended this research to validate the developed mathematical models as an effective prediction tool of the performances of the OWCP and further increase the efficiency of water removal that can be achieved.

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43

Lee, Hyun Yup. "Drillstring axial vibration and wave propagation in boreholes". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13907.

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44

Van, der Westhuysen A. J. "The application of the numerical wind wave model SWAN to a selected field case on the South African coast". Thesis, Link to the online version, 2002. http://hdl.handle.net/10019.1/3632.

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45

McAllister, Mark Laing. "Analysis of laboratory and field measurements of directionally spread nonlinear ocean waves". Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28762.

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Surface gravity waves exist in the oceans as multi-directional nonlinear phenomena. Understanding how these two properties interact is intrinsically important in itself. Furthermore, an understanding of this relationship may be used to gain insight into other oceanic phenomena. This thesis first describes an experimental investigation into the relationship between directionality and non-linearity (Part I). This relationship was then used as a tool to estimate the directional spreading of field data (Part II). Experiments have been conducted in which directionally spread focused wave groups were created in a wave tank. The relationship between the degree of directional spreading and the second-order bound harmonics of the wave groups was examined, in particular the formation of a `set-up'. These measurements were then compared to predictions from second-order theories, finding good agreement. The two-dimensional structure of the bound waves was explored giving new insight into the underlying physics. Experiments were then carried out for directionally spread crossing wave groups. It is believed that the crossing of two sufficiently separated wave groups may be the cause of an anomalous set-up in the second-order bound waves observed for some extreme and potentially freak waves. This set-up is reproduced experimentally. Again, the results of these test agreed very well when compared to second-order theory. The insight gained from the foregoing experiments was then utilised in the analysis of field data. A method, which requires only a single measurement to estimate the observed degree of directional spreading, was applied to a large dataset of field measurements from the North Alwyn platform in the North Sea. This method was then compared to conventional approaches, which require multiple concurrent measurements. The method that requires only a single measurement was shown to be effective, and presents a promising approach to gaining additional insight about the directional spreading of point observations.

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46

Qin, Wenting. "Application of the spectral wave model SWAN in Delaware Bay". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 4.68 Mb., 130 p, 2005. http://proquest.umi.com/pqdlink?did=1037889341&Fmt=7&clientId=8331&RQT=309&VName=PQD.

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47

Cureton, Geoffrey Patrick. "Retrieval of nonlinear spectral information from ocean sunglint". Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1549.

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In this thesis we develop an inversion procedure which allows the retrieval of nonlinear characteristics of the ocean wave surface from observations of specularly reflected visible solar radiation, or sunglint. Knowledge of the higher order statistical properties of the wave surface enables us to gain an improved understanding of wave generation processes, to determine the degree of energy transfer between wave components, and to make statements about the likelihood of extreme or unlikely wave events. Apart from its scientific value, this information should be useful for the engineering of maritime structures, where account must be made of conditions occasionally exceeding what a structure is normally expected to withstand.Previous attempts at retrieving information about the ocean surface from sunglint data (Alvarez-Borrego, 1993) have used second order statistical descriptors, such as the variance and autocorrelation, to provide the connection between the slope and sunglint data. This approach results in the loss of phase information from the slope and sunglint statistical descriptors, which prevents the retrieval of the phase correlations between the wave components arising from nonlinear interactions.In order to address this deficiency, we derive the relationship between the slope and the sunglint data in terms of their respective third order cumulant functions. The glint function in this case is defined in terms of the corresponding joint slope probability density. This density function is developed using a perturbative approach, and consists of a Gaussian function (which characterises the second order statistical descriptors of the slope), and corrections which parameterise the higher order correlations between the slope variables. A consequence of this approach to synthesising the required slope density is a dependence on higher order, or Multidimensional Hermite Polynomials (MDHP). Accordingly, the differential and integral properties of these orthogonal polynomials are investigated with respect to their utility in formulating the slope density function.Using these tools, we develop an inversion procedure which exploits the generalised relationship connecting the statistical descriptors of the slope and glint to retrieve the slope descriptors, namely the slope cumulants and third order cumulant function. This technique is validated using synthetic ocean wave slope datasets with controlled phase correlations imposed on a subset of the wave spectrum components.

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48

Wallace, Stephanie. "The relationship between ocean wave statistics and satellite measurements". Thesis, The University of Sydney, 1993. https://hdl.handle.net/2123/26654.

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Wave statistics are the basis of offshore and coastal designs. Engineers rely on these parameters to estimate extreme waveheights which are the cause of structural damage and shipping disasters. Satellites are the tools of the future, particularly in the study of the oceans, as no other instruments are capable of providing extensive continuous global coverage over such a vast region. The predominant aim of this thesis is to analyse temporal wave statistics and to determine if these measurements are applicable to spatial waveheight measurements made from satellite altimeters. This was approached by examining waveheight measurements using several statistical properties of samples over both time and space. Time series recordings of waveheights were made with sonic wave gauges at two platforms in Bass Strait, together with the permanent Weather Station system. The variability of waveheights over both time and space was examined using the three instruments, and was found to demonstrate significant waveheight (HS) fluctuations despite relatively steady conditions. Probability distributions, which are the foremost method for describing the sea surface, were then applied to the temporal waveheight files to see which were the most suitable for maxima and waveheight prediction. Temporal correlations were made from continuous waveheight measurements obtained from the Weather Station and its predecessor instrument, the Baylor Wave Gauge. These curves were then compared with spatial correlations drawn from the GEOSAT satellite Hs values, and the two statistics were found to be in good agreement. Groups of high waves were examined in the temporal waveheight files using the envelope theory. The average number of waves per group were found to vary considerably in a 1024 second file, and a wave age dependency was evident. The propagation of the Wave groups was then considered to see if a similar measurement would be found in the spatial instantaneous footprint of the altimeter. In order to directly compare temporally and spatially derived ocean parameters (other than HS), it is necessary to know how many waves are contained in the altimeter footprint. This can be estimated if the crestlength and wavelength are known. Therefore the relationship between these two parameters and wave age (which may also affect crestlength) were examined, and crestlength was found to vary under different conditions and seas of different ages.

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49

Siddorn, Philip David. "Efficient numerical modelling of wave-structure interaction". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:de36bd2f-cd23-4f11-b67f-9d8cd48ecd3c.

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Offshore structures are required to survive in extreme wave environments. Historically, the design of these offshore structures and vessels has relied on wave-tank experiments and linear theory. Today, with advances in computing power, it is becoming feasible to supplement these methods of analysis with fully nonlinear numerical simulation. This thesis is concerned with the development of an efficient method to perform this numerical modelling, in the context of potential flow theory. The interaction of a steep ocean wave with a floating body involves a moving free surface and a wide range of length scales. Attempts to reduce the size of the simulation domain cause problems with wave reflection from the domain edge and with the accurate creation of incident waves. A method of controlling the wave field around a structure is presented. The ability to effectively damp an outgoing wave in a very short distance is demonstrated. Steep incident waves are generated without the requirement for the wave to evolve over a large time or distance before interaction with the body. This enables a general wave-structure interaction problem to be modelled in a small tank, and behave as if it were surrounded by a large expanse of water. The suitability of the boundary element method for performing this modelling is analysed. Potential improvements are presented with respect to accuracy, robustness, and computational complexity. Evidence of third order diffraction is found for an FPSO model.

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50

Brookins, A. Henry. "Ocean wave height transformation model using surface roller theory". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA272610.

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Tesi sul tema "Ocean Wave"

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