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1
Abreu, Manuel P. "Kinematics under wind waves". Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/27115.
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2
Hurley, David Lee. "Wind waves and internal waves in Base Mine Lake". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62524.
Testo completoAbstract (sommario):
Syncrude's Base Mine Lake is the first commercial scale demonstration of end pit lake technology in the Canadian Oil Sands. Following its commissioning in 2012 significant efforts have been made to monitor and understand its evolution. Of particular interest is the impact of surface and internal waves on the resuspension of fluid fine tailings and the effect of hydrocarbons on surface wind wave formation and growth. In this study the first complete description of the wind and internal waves in Base Mine Lake is presented.
Observations of surface wind waves were collected using two subsurface pressure gauges. Data revealed that wind waves in Base Mine Lake have short residence times and rarely generate bottom orbital velocities capable of resuspending fluid fine tailings. Additionally, numerical simulations of the wind waves in Base Mine Lake were performed with the SWAN model. Modeled wave heights were in good agreement with observations, and resuspension of fluid fine tailings was minimal even during the 10 year storm event.
As the surface of Base Mine Lake contains a hydrocarbon film its impact on surface wind waves was investigated in the laboratory and field. It was found that the hydrocarbon film dampens high frequency wind waves and results in a slower growing wind wave field dominated by longer wavelengths. Additionally, the presence of hydrocarbons also increases the critical wind speed needed to initiate wave growth. From these findings it is postulated that the hydrocarbon film on Base Mine Lake acts to decrease the fluxes of momentum, gas, and heat.
The internal waves in Base Mine Lake were simulated using Delft3D Flow. Simulated wave heights as large as 3 m were shown to oscillate for multiple days with little dampening, and despite the small surface area of Base Mine Lake (8 km²) the internal waves were significantly influenced by the Coriolis force. This influence was seen in the form of simulated Kelvin and Poincaré waves which resulted in complex circulation patterns within the lake. The findings presented here provide a first picture into the impacts of waves on the reclamation of Base Mine Lake.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
3
Kukulka, Tobias. "The effect of breaking waves on a coupled model of wind and ocean surface waves". View online ; access limited to URI, 2006. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3248233.
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4
Kwon, Sun Hong. "Directional growth of wind generated waves". Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49816.
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5
Kalmikov, Alexander G. "Modeling wind forcing in phase resolving simulation of nonlinear wind waves". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57791.
Testo completoAbstract (sommario):
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), 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 148-152).
Wind waves in the ocean are a product of complex interaction of turbulent air flow with gravity driven water surface. The coupling is strong and the waves are non-stationary, irregular and highly nonlinear, which restricts the ability of traditional phase averaged models to simulate their complex dynamics. We develop a novel phase resolving model for direct simulation of nonlinear broadband wind waves based on the High Order Spectral (HOS) method (Dommermuth and Yue 1987). The original HOS method, which is a nonlinear pseudo-spectral numerical technique for phase resolving simulation of free regular waves, is extended to simulation of wind forced irregular broadband wave fields. Wind forcing is modeled phenomenologically in a linearized framework of weakly interacting spectral components of the wave field. The mechanism of wind forcing is assumed to be primarily form drag acting on the surface through wave-induced distribution of normal stress. The mechanism is parameterized in terms of wave age and its magnitude is adjusted by the observed growth rates. Linear formulation of the forcing is adopted and applied directly to the nonlinear evolution equations. Development of realistic nonlinear wind wave simulation with HOS method required its extension to broadband irregular wave fields. Another challenge was application of the conservative HOS technique to the intermittent non-conservative dynamics of wind waves. These challenges encountered the fundamental limitations of the original method. Apparent deterioration of wind forced simulations and their inevitable crash raised concerns regarding the validity of the proposed modeling approach. The major question involved application of the original HOS low-pass filtering technique to account for the effect of wave breaking. It was found that growing wind waves break more frequently and violently than free waves.
(cont.) Stronger filtering was required for stabilization of wind wave simulations for duration on the time scale of observed ocean evolution. Successful simulations were produced only after significant sacrifice of resolution bandwidth. Despite the difficulties our modeling approach appears to suffice for reproduction of the essential physics of nonlinear wind waves. Phase resolving simulations are shown to capture both - the characteristic irregularity and the observed similarity that emerges from the chaotic motions. Energy growth and frequency downshift satisfy duration limited evolution parameterizations and asymptote Toba similarity law. Our simulations resolve the detailed kinematics and the nonlinear energetics of swell, windsea and their fast transition under wind forcing. We explain the difference between measurements of initial growth driven by a linear instability mechanism and the balanced nonlinear growth. The simulations validate Toba hypothesis of wind-wave nonlinear quasi-equilibrium and confirm its function as a universal bound on combined windsea and swell evolution under steady wind.
by Alexander G. Kalmikov.
S.M.
6
Power, Jonathan. "Human temperature regulation in wind and waves". Thesis, University of Portsmouth, 2012. https://researchportal.port.ac.uk/portal/en/theses/human-temperature-regulation-in-wind-and-waves(38d9b1df-8d85-431a-afc4-66d1a44aa4c8).html.
Testo completoAbstract (sommario):
Many international and national standards exist for the testing and certification of immersion suits. Some require the thermal protective properties of immersion suits to be tested with human volunteers in calm, circulating 2°C water. The knowledge gap that currently exists between the benign testing conditions used in international standards and specifications, and the harsh environments that an immersed individual find themselves in following a marine accident, could result in unexpectedly poor levels of performance, with fatalities occurring sooner than expected following accidental immersion. Study 1 determined the heat loss from the skin of volunteers in immersion suits and immersed in wind and waves. Twelve healthy participants (Age: 25.8 [5.9] years old; Mass: 81.7 [13.1]kg; Height: 176.2 [7.7]cm) performed four, one hour immersions in the following conditions: Calm water; Wind-only; Waves-only; and Wind + Waves. Compared to Calm (67.21 [4.70]W·m-2), all the other immersion conditions produced a significantly greater increase in mean skin heat flow (MSHF) (Wind: 79.60 [6.70]W·m-2; Waves: 78.8 [4.52]W·m-2; Wind + Waves: 92.00 [8.39]W·m-2). The Wind + Waves condition produced a significantly greater increase in MSHF compared to all other conditions. Study 2 built upon the findings of the first by investigating the extent to which human thermal responses were related to the severity of weather conditions. Twelve healthy males (Age: 23.9 [3.3] years old; Mass: 83.2 [4.9]kg; Height: 181.0 [4.9]cm) performed three, three hour immersions in the following conditions: Calm water; Weather 1; and Weather 2. Compared to the calm water condition (62.96 [2.98]W·m-2], both weather conditions produced a significantly greater increase in MSHF (Weather 1: 76.75 [6.26]W·m-2; Weather 2: 79.53 [6.24]W·m-2). There were no significant differences in the change in gastro-intestinal temperature (TGI) across immersion conditions (Calm: -0.10 [0.31]°C; Weather 1: -0.29 [0.30]°C; Weather 2: -0.20 [0.28]°C]. There were no significant differences in V · O2 across immersion conditions (Calm: 0.325 [0.054]L·min-1; Weather 1: 0.332 [0.108]L·min-1; Weather 2: 0.365 [0.080]L·min-1). Study 3 investigated the effect of simulated water ingress under an immersion suit on human thermal responses during immersions in varying weather conditions. Twelve healthy males (Age: 25.6 [5.6] years old; Mass: 82.7 [10.2]kg; Height: 181.0 [4.7]cm) performed three, three hour immersions in the same conditions as Study 2, but with 500mL of water underneath the immersion suit. Compared to the calm water condition (79.45 [9.19]W·m-2), both weather conditions produced a significantly greater increase in MSHF (Weather 1: 102.06 [11.98]W·m-2; Weather 2: 107.48 [3.63]W·m-2). There were no significant differences in the change in TGI (Calm: -0.35 [0.14]°C; Weather 1: -0.38 [0.15]°C; Weather 2: 0.29 [0.25]°C) or V · O2 (Calm: 0.449 [0.054]L·min-1; Weather 1: 0.503 [0.051]L·min-1; Weather 2: 0.526 [0.120]L·min-1) across conditions. Survival times were calculated for the participants of Studies 2 and 3. There was no difference in the predicted survival times for the Study 2 participants for both the calm (> 36 hours) and wind and wave conditions (> 36 hours). The predicted survival times for the participants of Study 3 were significantly lower in the turbulent conditions (16 hours) compared to calm (27 hours). The predicted survival times of the participants in turbulent conditions were up to half those calculated for calm water immersions. The results collected in Studies 2 and 3 were used to calculate the change in total insulation in varying conditions compared to being dry. Immersions in wind and waves will reduce immersion suit insulation by 27%; 500mL of water leakage will reduce it by 24%; wind, waves and 500mL of water combined will reduce it by 43%. The predicted amount of oxygen consumption (V · O2 P) to produce the amount of heat required to remain in thermal balance can be estimated by rearranging the equations used to calculate metabolic heat production and insulation. If heat loss exceeds the assumed maximum heat production of 206W·m-2, hypothermia will eventually develop. The point at which heat loss exceeds maximum heat production has been determined in a range of conditions. It is concluded that: immersions in wind and waves causes a significant increase in heat flow from the body compared to calm conditions. Testing individuals and immersion suits in conditions not representative of the area where they are to be used may, or may not, result in an over-estimation of performance depending on the capacity of an individual’s thermoregulatory system.
7
Saxena, Gaurav. "Air flow separation over wind generated waves". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 235 p, 2007. http://proquest.umi.com/pqdweb?did=1251900711&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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8
Smith, George Henry. "A laboratory study of wind generated waves". Thesis, Heriot-Watt University, 1985. http://hdl.handle.net/10399/1948.
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9
Walker, Wayne O. "Field measurements of local pier scour in a tidal inlet". Thesis, (10.49 MB), 1995. http://handle.dtic.mil/100.2/ADA303503.
Testo completoAbstract (sommario):
Thesis (M.S. in Civil Engineering)--University of Florida, December 1995."December 1995." Description based on title screen as viewed on February 8, 2010. DTIC Identifier(s): Scouring, Wind Waves, Sieve Analysis, Seiching. Includes bibliographical references (p. 139). Also available in print.
10
Fuchs, David M. R. "2D spectral modeling of wind-waves on inland lakes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ45045.pdf.
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11
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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12
Trevett, William Lawrence. "Statistical Investigation of Langmuir Waves in the Solar Wind". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29809.
Testo completoAbstract (sommario):
Type II and III solar radio bursts involve streaming electrons that produce Langmuir waves that then couple wave energy into radio emission. These Langmuir waves can be driven to large enough amplitudes that they undergo electrostatic (ES) decay into a backward propagating Langmuir wave and forward propagating ion acoustic wave. The forward and backwards propagating Langmuir waves can then “beat” together to produce characteristic Langmuir waveforms and spectra, plus radio emission. Stochastic growth theory (SGT) predicts that the probability distribution of the Langmuir wave electric field strength should be lognormal, with known modifications if nonlinear processes like ES decay are occurring. Other analyses suggest Pearson distributions may be relevant. Here, previous work on Langmuir waves in type II and III source regions is generalized and tested by analysing the probability distributions of the waveforms of Langmuir waves observed by the STEREO spacecraft. The focus is on a set of published events identified using spectral analyses to have or not have spectral evidence for ES decay. For events for which spectral analyses provide evidence of ES decay, 86% of the probability distributions are consistent with the combination of SGT and a nonlinear process like ES decay, while of those without spectral evidence for ES decay 78% of the probability distributions are well fitted by pure SGT. Moreover, better fits with stronger statistical significance are obtained for pure and nonlinear SGT than for Pearson distributions in the majority of events (∼ 90%). These results provide strong evidence for SGT and ES decay proceeding in type II and III source regions.
13
Lee, Eunji (Jubee). "After the big wind stops I see gentle waves". VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5367.
Testo completoAbstract (sommario):
This thesis covers my reflections on the inspirations and the motivations behind selected works including my candidacy exhibition; Resonance and my thesis exhibition; after the big wind stops I see gentle waves. It contains my life throughout my MFA studies and the development of my art practice. Through its story-within-a-story method of narration and my describing streams of my thoughts, I am attempting to explain the processes of my development and the discoveries I have made, the little things in my daily life, and the big turning points that inspired me. My work and this document have been strongly determined by my poetic imagination and the emotional events and experiences I have had.
14
SANS, JIMÉNEZ ALEJANDRO, e LÓPEZ ANTONIO RICARDO BARCELÓ. "Characterisation of Waves and Wind Loads on Floating Bridges". Thesis, KTH, Bro- och stålbyggnad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-267041.
Testo completoAbstract (sommario):
Floating bridges are complex and unusual structures. There are very fewfloating bridges built in the world so there is not much information about them. Besides, its condition of floating structure makes it an interdisciplinary structure with maritime and marine engineering.Probably their most peculiar characteristic is that their sustenance is pro duced by floaters and mooring lines that provide special boundary conditions to the structure. The lack of transverse stiffness is also an important feature that makes this structure particularly sensitive to lateral loads. Therefore, the correct definition of the environmental lateral loads is crucial. It is during storms that floating bridges can collapse due to the wind and waves.The aim of this thesis is to deal with the special conditions of floating bridges and to go deep into the theory of wind and waves. With this, it is intended to specify calculation methodologies with which to correctly assess these im portant environmental loads.
15
Marino, Enzo [Verfasser], e Udo [Akademischer Betreuer] Peil. "An integrated nonlinear wind-waves model for offshore wind turbines / Enzo Marino ; Betreuer: Udo Peil". Braunschweig : Technische Universität Braunschweig, 2010. http://d-nb.info/1175826022/34.
Testo completo
16
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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17
Akbasoglu, Sinan. "Short-term Statistics Of Wind Waves Around The Turkish Coast". Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604722/index.pdf.
Testo completoAbstract (sommario):
In this thesis, the wind-wave records obtained at three locations along the Turkish coasts (Alanya, Dalaman and Hopa) are analyzed. Probability distributions of individual wave characteristics (wave height, wave period and wave steepness) are obtained and compared with the model distributions. Goodness of fit of the observed distributions is checked by Chi-square test and Kolmogorov-Smirnov tests. Joint probability distribution of individual wave heights and periods is also studied and compared with the theoretical distributions. The relationships among various statistical wave height parameters and statistical wave period parameters are investigated and compared with the theoretical and reported values.
18
Yilmaz, Nihal. "Spectral Characteristics Of Wind Waves In The Eastern Black Sea". Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608614/index.pdf.
Testo completoAbstract (sommario):
Wind waves are highly complex, random phenomena. One way to describe the irregular nature of the sea surface is the use of wave energy spectrum. Spectral information for wind waves in the Black Sea is extremely limited. Knowledge on spectral characteristics of wind waves would contribute to scientific, engineering and operational coastal and marine activities in the Black Sea. The aim of the present thesis is to investigate characteristics of wind wave spectra for the Eastern Black Sea. This would allow detailed understanding of the nature of the waves occurring in this enclosed basin. Long-term wave measurements obtained by directional buoys deployed offshore at Sinop, Hopa and Gelendzhik were utilized as the three sets of wave data. Records were analyzed to identify them as uni-modal or multi-modal spectra, and occurrences of spectral peaks were computed. Single peaked spectra were studied as belonging to fully arisen or developing sea states. Model parameters of JONSWAP and PM spectra were estimated for the observed spectra by using a least square error method. The records of developing seas were further analyzed to select the ones belonging to stable wind conditions. Fetch dependencies of non-dimensional spectral variables, mean parameters of JONSWAP model spectrum and the envelop of dimensionless spectra were investigated for this data sub-set.
19
Janajrah, Ma'moun Ali Mohammad. "An investigation of the mechanisms of wind generated surface waves". Thesis, University of Hertfordshire, 2010. http://hdl.handle.net/2299/4524.
Testo completoAbstract (sommario):
The goal of wind-waves research is to predict the waves field and its effect on the environment. That environment could be natural or imposed by human endeavour. The mechanism of wind generated waves is described in the present work as a wind-bulk flow interaction rather than as a mechanical process which only transfers the wind energy to the wave. In the light of this description, the generation and growth of surface waves are functions of the physical properties of the interface, density of the bulk flow perturbations and wind shear stress. While the present models for the prediction of surface growth and evolution show some consistence - in some cases - with observations that were conducted in laboratories and in real fields, the work presented in this thesis justifies and explains the inconsistency or contradictions in other cases between the observations and the predictions. Also, physical interpretations for observations, for example wave growth with fetch, are suggested in the present work. To illustrate the physical mechanism responsible for wave generation and growth under the effect of wind action, two approaches are used. The first involves studying the effect of the physical properties of the water surface on atmospheric input into the bulk and thus the effect on the formation and growth of capillary waves. The second involves studying the correlation between the wave formation and growth and the density of the bulk perturbations. Wide ranges of previous data are used to analyse the effect of the physical properties of the water surface on wave generation and growth mechanism for the first approach. Also, a group of experiments using the PIV system (Particle Image Velocimetry) were conducted to study the correlation between the wind speed, bulk flow evolution and wind-waves‟ generation and growth for the second approach. The main physical parameters which are responsible for the generation and growth of capillary waves are determined. The Ohnesorge number is modified to predict the generation and growth of surface waves. In the second part, additional physical parameters of the bulk flow are introduced to illustrate the correlation between the wind generated waves and bulk flow evolution. A new parameter is used to scale the transition of the bulk flow from laminar flow to turbulent flow or the transition of the water surface from an undisturbed surface to a fully disturbed surface. The history of wind-wave research is relatively short. Although there were basic developments in the 18th century, a concentrated effort really began as a result of the military imperative of the Second World War. These developments were however, largely empirical. A theoretical frame work began to develop with the studies of wind-wave generation in the last century. The present work is conducted to fill some gaps in wind generated surface waves research and to introduce new approaches to simplify understanding wind-waves field and its effect on the environment.
20
Xie, Zhihua. "Numerical modelling of breaking waves under the influence of wind". Thesis, University of Leeds, 2010. http://etheses.whiterose.ac.uk/939/.
Testo completoAbstract (sommario):
Wave breaking plays an important role in air-sea interaction, surf zone dynamics, nearshore sediment transport, marine hydrodynamics, and wave-structure interaction. When the wind is blowing over water waves, it not only enhances the exchanges of heat, mass and momentum on the air-water interface, but also affects the wave breaking process. The objective of this thesis is to contribute to the understanding of breaking waves under the influence of wind. A two-phase flow model is presented to solve the flow in the air and water simultaneously. Two strategies for turbulence modelling, namely, the Reynolds-averaged Navier–Stokes (RANS) equations with the k−ǫ turbulence model and Large Eddy Simulation (LES) with the Smagorinsky subgrid-scale model, are employed to study two-dimensional (2D) and three-dimensional (3D) breaking waves, respectively. The governing equations are solved by the finite volume method in a Cartesian staggered grid and the partial cell treatment is implemented to deal with complex geometries. The SIMPLE or PISO algorithms are utilized for the pressure-velocity coupling and a backward finite difference discretization is used for the time derivative. The air-water interface is modelled by the interface capturing method via a high resolution VOF (Volume of Fluid) scheme. The numerical model is validated by simulating 2D overturning waves on a sloping beach and over a reef, and 3D solitary wave run-up on a conical island, in which good agreement between numerical results and experimental measurements is obtained. Moreover, the overturning jet and subsequent splash-up are captured in the computation. The numerical model is further employed to investigate 2D breaking solitary waves on a sloping beach, 2D periodic breaking waves (both spilling and plunging breakers) in the surf zone, and 3D overturning waves over a submerged conical island. Numerical results in the absence of wind are presented and compared with available experimental data, and then the effect of wind is included in the computation of breaking waves. The key findings of this thesis are that the wind can influence the kinematics and dynamics of breaking waves, as onshore winds assist the development of water particle velocities towards the critical wave phase speed, cause the wave to break earlier in a deeper water further off shore. There is recirculation of air flow above the wave crest in the absence of wind whereas air flow separation is observed in the presence of a sufficiently strong wind. In addition, the wind affects the shape of the overturning jet, generation of vorticity, and energy transformation and dissipation during wave breaking. This study has contributed to the characteristics of breaking waves, focusing on the period during wave overturning. The information gained in this study shed some light on wind effects on breaking waves, which have import implications for coastal engineering and air-sea interaction.
21
Watts, Kristen Peta. "Fetch-limited wind wave generation on the continental shelf". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FWatts.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in Physical Oceanography)--Naval Postgraduate School, December 2003.Thesis advisor(s): Thomas H.C. Herbers, Edward B. Thornton. Includes bibliographical references (p. 71-73). Also available online.
22
Haag, Christian. "Temporal and spatial wind field distribution in Delaware Bay". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 9.11 Mb., 62 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1430767.
Testo completoAbstract (sommario):
Thesis (M.E.E.)--University of Delaware, 2006.Principal faculty advisors: Kenneth E. Barner, Dept. of Electrical and Computer Engineering; and Mohsen Badiey, Dept. of Marine and Earth Studies. Includes bibliographical references.
23
Masson, Diane. "Spectral evolution of wind generated surface gravity waves in a dispersed ice field". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/29020.
Testo completoAbstract (sommario):
The Marginal Ice Zone includes wide areas covered by dispersed ice floes in which wave conditions are significantly affected by the ice. When the wind blows from the solid ice pack, towards the open sea, growing waves are scattered by the floes, their spectral characteristics being modified. To further understand this problem, a model for the evolution of wind waves in a sparse field of ice floes was developed. The sea state is described by a two-dimensional discrete spectrum. Time-limited wave growth is obtained by numerical integration of the energy balance equation using the exact nonlinear transfer integral. Wave scattering by a single floe is represented in terms of far-field expressions of the diffracted and forced potentials obtained numerically by the Green's function method. The combined effect of a homogeneous field of floes on the wave spectrum is expressed in terms of the Foldy-Twersky integral equations under the assumption of single scattering. The results show a strong dependence of the spectrum amplitude and directional properties on the ratio of the ice floe diameter to the wavelength. For a certain range of this parameter, the ice cover appears to be very effective in dispersing the energy; the wave spectrum rapidly tends to isotropy, limiting its growth both for the energy content and the peak frequency. It is therefore unlikely that an offshore wind blowing over the Marginal Ice Zone would generate a significant wave field.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
24
Russell, Alexander J. B. "Coupling of the solar wind, magnetosphere and ionosphere by MHD waves". Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/2571.
Testo completoAbstract (sommario):
The solar wind, magnetosphere and ionosphere are coupled by magnetohydrodynamic waves, and this gives rise to new and often unexpected behaviours that cannot be produced by a single, isolated part of the system. This thesis examines two broad instances of coupling: field-line resonance (FLR) which couples fast and Alfvén waves, and magnetosphere-ionosphere (MI-) coupling via Alfvén waves. The first part of this thesis investigates field-line resonance for equilibria that vary in two dimensions perpendicular to the background magnetic field. This research confirms that our intuitive understanding of FLR from 1D is a good guide to events in 2D, and places 2D FLR onto a firm mathematical basis by systematic solution of the governing equations. It also reveals the new concept of ‘imprinting’ of spatial forms: spatial variations of the resonant Alfvén wave correlate strongly with the spatial form of the fast wave that drives the resonance. MI-coupling gives rise to ionosphere-magnetosphere (IM-) waves, and we have made a detailed analysis of these waves for a 1D sheet E-region. IM-waves are characterised by two quantities: a speed v_{IM} and an angular frequency ω_{IM} , for which we have obtained analytic expressions. For an ideal magnetosphere, IM-waves are advective and move in the direction of the electric field with speed v_{IM}. The advection speed is a non-linear expression that decreases with height-integrated E-region plasma-density, hence, wavepackets steepen on their trailing edge, rapidly accessing small length-scales through wavebreaking. Inclusion of electron inertial effects in the magnetosphere introduces dispersion to IM-waves. In the strongly inertial limit (wavelength λ << λ_{e} , where λ_{e} is the electron inertial length at the base of the magnetosphere), the group velocity of linear waves goes to zero, and the waves oscillate at ω_{IM} which is an upper limit on the angular frequency of IM-waves for any wavelength. Estimates of v_{IM} show that this speed can be a significant fraction (perhaps half) of the E_{⊥} × B_{0} drift in the E-region, producing speeds of up to several hundred metres per second. The upper limit on angular frequency, ωIM , is estimated to give periods from a few hundredths of a second to several minutes. IM-waves are damped by recombination and background ionisation, giving an e-folding decay time that can vary from tens of seconds to tens of minutes. We have also investigated the dynamics and steady-states that occur when the magnetosphere-ionosphere system is driven by large-scale Alfvénic field-aligned currents. Steady-states are dominated by two approximate solutions: an ‘upper’ solution that is valid in places where the E-region is a near perfect conductor, and a ‘lower’ solution that is valid where E-region depletion makes recombination negligible. These analytic solutions are extremely useful tools and the global steady-state can be constructed by matching these solutions across suitable boundary-layers. Furthermore, the upper solution reveals that E-region density cavities form and widen (with associated broadening of the magnetospheric downward current channel) if the downward current density exceeds the maximum current density that can be supplied by background E-region ionisation. We also supply expressions for the minimum E-region plasma-density and shortest length-scale in the steady-state. IM-waves and steady-states are extremely powerful tools for interpreting MI-dynamics. When an E-region density cavity widens through coupling to an ideal, single-fluid MHD magnetosphere, it does so by forming a discontinuity that steps between the upper and lower steady-states. This discontinuity acts as part of an ideal IM-wave and moves in the direction of the electric field at a speed U = \sqrt{v_{IM} {+} v_{IM} {-}}, which is the geometric mean of v_{IM} evaluated immediately to the left and right of the discontinuity. This widening speed is typically several hundreds of metres per second. If electron inertial effects are included in the magnetosphere, then the discontinuity is smoothed, and a series of undershoots and overshoots develops behind it. These undershoots and overshoots evolve as inertial IM-waves. Initially they are weakly inertial, with a wavelength of about λ_{e}, however, strong gradients of ω_{IM} cause IM-waves to phase-mix, making their wavelength inversely proportional to time. Therefore, the waves rapidly become strongly inertial and oscillate at ω_{IM}. The inertial IM-waves drive upgoing Alfvén waves in the magnetosphere, which populate a region over the downward current channel, close to its edge. In this manner, the E-region depletion mechanism, that we have detailed, creates small-scale Alfvén waves in large-scale current systems, with properties determined by MI-coupling.
25
Zhang, Ni. "Estimating Wind Velocities in Atmospheric Mountain Waves Using Sailplane Flight Data". Thesis, University of Canterbury. Electrical and Computer Engineering, 2012. http://hdl.handle.net/10092/7618.
Testo completoAbstract (sommario):
Atmospheric mountain waves form in the lee of mountainous terrain under appropriate conditions of the vertical structure of wind speed and atmospheric stability. Trapped lee waves can extend hundreds of kilometers downwind from the mountain range, and they can extend tens of kilometers vertically into the stratosphere. Mountain waves are of importance in meteorology as they affect the general circulation of the atmosphere, can influence the vertical structure of wind speed and temperature fields, produce turbulence and downdrafts that can be an aviation hazard, and affect the vertical transport of aerosols and trace gasses, and ozone concentration.
Sailplane pilots make extensive use of mountain lee waves as a source of energy with which to climb. There are many sailplane wave flights conducted every year throughout the world and they frequently cover large distances and reach high altitudes. Modern sailplanes frequently carry flight recorders that record their position at regular intervals during the flight. There is therefore potential to use this recorded data to determine the 3D wind velocity at positions on the sailplane flight path. This would provide an additional source of information on mountain waves to supplement other measurement techniques that might be useful for studies on mountain waves. The recorded data are limited however, and determination of wind velocities is not straightforward.
This thesis is concerned with the development and application of techniques to determine the vector wind field in atmospheric mountain waves using the limited flight data collected during sailplane flights. A detailed study is made of the characteristics, uniqueness, and sensitivity to errors in the data, of the problem of estimating the wind velocities from limited flight data consisting of ground velocities, possibly supplemented by air speed or heading data. A heuristic algorithm is developed for estimating 3D wind velocities in mountain waves from ground velocity and air speed data, and the algorithm is applied to flight data collected during “Perlan Project” flights. The problem is then posed as a statistical estimation problem and maximum likelihood and maximum a posteriori estimators are developed for a variety of different kinds of flight data. These estimators are tested on simulated flight data and data from Perlan Project flights.
26
Trulsen, Karsten. "The influence of currents, long waves and wind on gravity-capilary". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36558.
Testo completo
27
Hildebrandt, Arndt [Verfasser]. "Hydrodynamics of breaking waves on offshore wind turbine structures / Arndt Hildebrandt". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2014. http://d-nb.info/1053540329/34.
Testo completo
28
Selzer, Luke A. "Fast magnetoacoustic waves in non-equilibrium solar wind and coronal plasmas". Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/74159/.
Testo completoAbstract (sommario):
In this thesis the effect of collective particle behaviour within a plasma was explored using kinetic plasma theory in conjunction with magnetohydrodynamics (MHD). Collisionless or quasi-collisionless space plasmas were used as test laboratories in an attempt to understand the evolution of space plasmas. In a collisionless plasma, forces and fields are mediated through collective behaviour such as instabilities and plasma waves, thus the plasma parameters evolve due to modification by collective effects. In this work we implemented analytical and numerical techniques to predict the effect of collective behaviour. These hypotheses were then tested against experimental data as a validation process. The region near the Earth’s bow shock where incoming solar wind interacts with plasma emanating from the bow shock is known as the foreshock. This region is an abundant source of complex particle distributions with associated collective phenomena. We report the first observation of correlation between elevated solar wind core plasma temperatures and temperature anisotropy in the terrestrial foreshock. Direct comparison of contemporaneous anisotropic temperatures in the upstream solar wind and the foreshock suggests that the net heating of plasma is mediated via a increase of the parallel temperature in the foreshock region where ultra low frequency (ULF) plasma waves have been observed. We consider the possibility that a mechanism based on Landau damping, where solar wind plasma temperature parallel to the background magnetic field is increased by interaction with oblique compressible fast magneto-acoustic ULF waves, influences temperature anisotropy. Next the impact of wave phenomena on the radio emission fine structure in flaring loops of the solar corona was investigated. In particular, the impact of MHD oscillations on zebra pattern (ZP) radio emission. Initially static analytical studies were carried in one and two dimensions to show it was possible do derive a ZP using MHD techniques. The dynamics of ZP formation in the presence of MHD oscillations were then analytically studied to show the presence of ‘wiggles’ in the ZP. These results were then repeated using numerical simulations using the Lare2D MHD code. The catalogue of results suggests that the detected ZP wiggles were caused by a standing sausage oscillation. We affirm this conclusion using the observation that both instant frequencies of individual stripes and their spectral separation oscillate with the same periods. Thus it is consistent with a sausage oscillation that perturb both the plasma density and magnetic field. These results are further underpinned by comparison to experimentally obtained ZP wiggles which exhibit similar periodicities. This new result could lead to a method for the direct measurement of coronal magnetic fields in flaring loops.
29
Byars, Beverly J. "Variation of the drag coefficient with wind and wave state". Thesis, Monterey, Calif. : Naval Postgraduate School, 1985. http://catalog.hathitrust.org/api/volumes/oclc/52763691.html.
Testo completo
30
Sajjadi, S. G. "A mechanism for the transfer of energy from wind to water waves". Thesis, Coventry University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382219.
Testo completo
31
Vech, Daniel, Kristopher G. Klein e Justin C. Kasper. "Nature of Stochastic Ion Heating in the Solar Wind: Testing the Dependence on Plasma Beta and Turbulence Amplitude". IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626264.
Testo completoAbstract (sommario):
The solar wind undergoes significant heating as it propagates away from the Sun; the exact mechanisms responsible for this heating are not yet fully understood. We present for the first time a statistical test for one of the proposed mechanisms: stochastic ion heating. We use the amplitude of magnetic field fluctuations near the proton gyroscale as a proxy for the ratio of gyroscale velocity fluctuations to perpendicular (with respect to the magnetic field) proton thermal speed, defined as epsilon(p). Enhanced proton temperatures are observed when epsilon(p) is larger than a critical value (similar to 0.019-0.025). This enhancement strongly depends on the proton plasma beta (beta parallel to(p)); when beta parallel to(p) << 1 only the perpendicular proton temperature T-perpendicular to increases, while for beta parallel to(p) similar to 1 increased parallel and perpendicular proton temperatures are both observed. For epsilon(p) smaller than the critical value and beta parallel to(p) << 1 no enhancement of Tp is observed, while for beta parallel to(p) similar to 1 minor increases in T-parallel to are measured. The observed change of proton temperatures across a critical threshold for velocity fluctuations is in agreement with the stochastic ion heating model of Chandran et al. We find that epsilon(p) > epsilon(crit) in 76% of the studied periods, implying that stochastic heating may operate most of the time in the solar wind at 1 au.
32
Ghafoor, Nadeem A. L. "Modelling Titan's surface and dynamic simulation and testing of the Huygens surface science package tiltsensor (TIL)". Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269089.
Testo completo
33
Bopp, Maximilian [Verfasser], e Bernd [Akademischer Betreuer] Jähne. "Air-Flow and Stress Partitioning over Wind Waves in a Linear Wind-Wave Facility / Maximilian Bopp ; Betreuer: Bernd Jähne". Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177386887/34.
Testo completo
34
Caeiro, Olaio Valente Maria Antonia. "Effects of directional wind shear on orographic gravity wave drag". Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325212.
Testo completo
35
Holmbom, Joakim. "Modelling of Waves and Currents in the Baltic Sea". Thesis, KTH, Vattendragsteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96232.
Testo completoAbstract (sommario):
To facilitate the process of setting up small scale environmental models in coastal and offshore areas a wave model and a 2D current model for the Baltic Sea have been set up with MIKE 21. The ambition is that the Baltic Sea model can serve as a source of boundary conditions for local models. The main focus in the project has been to determine which input data to use to get the best results and then to calibrate and validate the model with the best data sets available. The wave model has been tested with three different sources of wind forcing and the results with the different sources are evaluated. The wave model has been calibrated and validated against five wave buoys and the current model against three current observation stations. The comparison shows that the wave model gives good estimations of wave height, period and direction. The output of the current model coincides with observations where distinct current patterns exist. The wave model is considered a good source to extract wave statistics from for the entire Baltic Sea. The current model can be used for scenarios or areas that do not suffer from the limitations of a 2D model.
36
Binz-Reist, Hans-Rudolf Binz Hans-Rudolf. "Mechanische Belastbarkeit natürlicher Schilfbestände durch Wellen, Wind und Treibzeug = Mechanical impacts on natural reed stands by wind, waves and drift /". Zürich : Geobotanisches Institut der ETH, 1989. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=8590.
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Dankert, Heiko. "Measurements of waves, wave groups and wind fields using nautical radar image sequences". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969854935.
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38
Hicks, Malcolm Andrew. "Geotechnical Investigations of Wind Turbine Foundations Using Multichannel Analysis of Surface Waves (MASW)". Thesis, University of Canterbury. Geological Sciences, 2011. http://hdl.handle.net/10092/6519.
Testo completoAbstract (sommario):
The geophysical technique known as Multichannel Analysis of Surface Waves, or MASW (Park et al., 1999) is a relatively new seismic characterisation method which utilises Rayleigh waves propagation. With MASW, the frequency dependent, planar travelling Rayleigh waves are created by a seismic source and then measured by an array of geophone receivers. The recorded data is used to image characteristics of the subsurface.
This thesis explains how MASW was used as a geotechnical investigation tool on windfarms in the lower North Island, New Zealand, to determine the stiffness of the subsurface at each wind turbine site. Shear‐wave velocity (VS) profiles at each site were determined through the processing of the MASW data, which were then used to determine physical properties of the underlying, weathered greywacke.
The primary research site, the Te Rere Hau Windfarm in the Tararua Ranges of the North Island, is situated within the Esk Head Belt of Torlesse greywacke (Lee & Begg, 2002). Due to the high level of tectonic activity in the area, along with the high rates of weathering, the greywacke material onsite is highly fractured and weathering grades vary significantly, both vertically and laterally. MASW was performed to characterise the physical properties at each turbine site through the weathering profile. The final dataset included 1‐dimensional MASW shear‐wave evaluations from 100 turbine sites. In addition, Poisson’s ratio and density values were characterised through the weathering profile for the weathered greywacke. During the geotechnical foundation design at the Te Rere Hau Windfarm site, a method of converting shear wave velocity profiles was utilised. MASW surveying was used to determine VS profiles with depth, which were converted to elastic modulus profiles, with the input parameters of Poisson’s ratio and density.
This study focuses on refining and improving the current method used for calculating elastic modulus values from shear‐wave velocities, primarily by improving the accuracy of the input parameters used in the calculation.
Through the analysis of both geotechnical and geophysical data, the significant influence of overburden pressure, or depth, on the shear wave velocity was identified. Through each of the weathering grades, there was a non‐linear increase in shear wave velocity with depth. This highlights the need for overburden pressure conditions to be considered before assigning characteristic shear wave velocity values to different lithologies.
Further to the dataset analysis of geotechnical and geophysical information, a multiple variant non‐linear regression analysis was performed on the three variables of shear wave velocity, depth and weathering grade. This produced a predictive equation for determining shear wave
velocity within the Esk Head belt ‘greywacke’ when depth and weathering data are known. If the insitu geological conditions are not comparable to that of the windfarm sites in this study, a set of guidelines have been developed, detailing the most efficient and cost effective method of
using MASW surveying to calculate the elastic modulus through the depth profile of an
investigation site.
39
Won, Younsang. "Higher order numerical schemes for propagation of wind wave spectra". Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39822.
Testo completo
40
Ling, Alister R. "Blocking-like flows in a hemispherical barotropic model". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65945.
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41
Renfrew, Ian Alasdair. "The development of secondary frontal cyclones". Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295008.
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42
Poulose, Jismy. "Interaction of storm tides with wind waves : coastal inundation along the west coast of India". Thesis, IIT Delhi, 2019. http://eprint.iitd.ac.in:80//handle/2074/8117.
Testo completo
43
Bendoni, Michele [Verfasser], e Hocine [Akademischer Betreuer] Oumeraci. "Salt marsh edge erosion due to wind-induced waves / Michele Bendoni ; Betreuer: Hocine Oumeraci". Braunschweig : Technische Universität Braunschweig, 2015. http://d-nb.info/117581881X/34.
Testo completo
44
Jacobi, Christoph, e Manfred Ern. "Gravity waves and vertical shear of zonal wind in the summer mesosphere-lower thermosphere". Universität Leipzig, 2013. https://ul.qucosa.de/id/qucosa%3A16408.
Testo completoAbstract (sommario):
Gravity wave amplitudes and momentum fluxes derived from SABER temperature measurements are analysed together with Collm meteor radar zonal winds. The momentum flux (MF) divergence derived from the SABER temperatures shows a maximum that is found at greater altitudes during solar minimum than during solar maximum. Therefore, the zonal mean wind and wind shear profiles are shifted upwards
then, leading to a modulation of the otherwise negative correlation between solar cycle and mesosphere/lower thermosphere winds.Amplituden von Schwerewellen und zugehörigen Impulsflüsse werden zusammen mit Windmessungen des Meteorradars Collm analysiert. Die Impulsflussdivergenz, abgeleitet aus SABER-Temperaturprofilen, hat ein Maximum welches im solaren Minimum nach oben verschoben ist. Dadurch werden auch die Vertikalprofile des Zonalwindes und der Windscherung nach oben verschoben, wodurch die ansonsten negative Sonnenfleckenzyklusabhängigkeit des zonalen Windes in der Mesosphäre/unteren Thermosphäre im solaren Minimum umgekehrt wird.
45
Semedo, Alvaro A. M. "The North Atlantic oscillation influence on the wave regime in Portugal : an extreme wave event analysis /". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FSemedo.pdf.
Testo completo
46
Yu, Xuri. "Dynamics of seasonal and interannual variability in the equatorial Pacific". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11065.
Testo completo
47
Eaves, Nicholas Mark. "Rising Waves, Breathless Wind. Lacan, Zen and Adolescence: Illuminating Śūnyatā in the Dualism of Education". Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/70506.
Testo completoAbstract (sommario):
Practising Receptance moves beyond simply receiving or accepting, as action in thinking, as intention towards openness to the other. Representations of us contrasted to the ‘real’ transcendental properties, founded in śūnyatā, sees us at the intersection of Lacan, Gadamer, and Zen Buddhism, where we have objects as they appear to us and objects that exist independently of us. How might we apprehend the reality of others and discern this reality from what we see?
48
Kakollu, Satyanarayana. "Numerical simulation of strong turbulence over water waves". Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-12112002-125436.
Testo completo
49
Jacobi, Christoph. "Solar cycle dependence of winds and planetary waves as seen from midlatitude mesopause region wind measurements at Collm". Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-213432.
Testo completoAbstract (sommario):
Windmessungen im Mesopausenbereich über Mitteleuropa (Collm, 52°N, I5°E) werden im Hinblick auf Langzeittrends und eine eventuelle Abhängigkeit vom 11-jährigen Sonnenfleckenzyklus hin untersucht. Der Einfluß der solaren Variabilität ist jahreszeitenabhängig; nur in Frühjahr und Sommer wird eine signifikante Korrelation gefunden. Im Sommer ist diese Abhängigkeit mit stärkeren vertikalen Gradienten des mittleren zonalen Grundwindes im solaren Maximum verbunden. Dies weist auf einen Ursprung dieser Abhängigkeit in der Stratosphäre/Mesosphäre sowie auf Koppelungsmechanismen zwischen Stratosphäre, Mesosphäre und unteren Thermosphäre hin. Da die 2-Tage-Welle vom Gradienten abhängt, führt dies zu einer positiven Korrelation zwischen der Amplitude der 2-Tage-Welle und der SonnenfleckenrelativzahlMesopause winds over Central Europe (Collm, 52°N, I5°E) are analysed with respect to longterm trends and 11-year solar cycle dependencies. The response of the prevailing wind to the solar cycle differs throughout the year. While in winter no significant correlation between the zonal prevailing wind and the solar activity is found, in spring and summer a negative correlation between solar activity and zonal prevailing wind can be seen from the measurements. This is connected with strenger vertical gradients of the zonal prevailing wind during solar maximum than during solar minimum. This hints to a forcing of the mesopause region dynamical reaction on solar activity from the stratosphere/mesosphere and to coupling processes in the stratosphere-mesosphere-lower thermosphere system. Since the amplitude of the quasi twoday wave is dependent on the zonal mean wind gradient, this is connected with a positive correlation between solar activity and quasi two-day wave activity
50
Ojha, Biswajit. "Solar wind control of wave activity in the magnetosphere". Thesis, IIG, 2022. http://library.iigm.res.in:8080/xmlui/handle/123456798/334.
Testo completo