This study provides the physical, mathematical and numerical basis of analysis work performed for predicting the flow around three-dimensional bluff body configurations. The flow has been treated as steady, incompressible, turbulent. The predictions were made using a two-equation turbulence model, solving transport equations for turbulence kinetic energy K and the turbulence dissipation rate ε, in addition to the partial differential equations for the conservation of mass and momentum. The program used was the well tested computer code "PHOENICS-84" based on work conducted by Prof. D.B. Spalding and Co-workers. Several computations have been performed, for three models: a single cube, a pair of cubes with different spacing, and a rudimentary representation of an offshore oil platform stucture. The prediction procedure was first tested for grid refinement and optimum solution domain size until profiles at several locations for selected variables showed little change with further increase of domain size and grid points. The effect of different wind directions was investigated for the three models; in addition, different pitching conditions of the oncoming flow were also considered for the platform-model configurations. Comparisons were made with wind tunnel test results on the same three models, and some discrepancies are noted, particularly in regions of separated, recirculating flow. Also comparisons were made with certain empirical calculation procedures used for wind load estimation in maritime engineering. Overall wind loading is nevertheless reasonably well predicted. Applications of the method in the area of wind loadings on a full scale offshore oil rig is discussed, and plans for refinement and extension of the present work are outlined. It is concluded that the present method can be used as a suitable starting point for generating a platform aerodynamics simulator. However, more work is required to this end, in order to represent adequately all aspects of platform-aerodynamics phenomena.

Freak waves suddenly strike the southwest of Taiwan, may cause damages of coastal structures, tourist facilities and endanger maritime navigation. The prediction of swells and large waves is under development. In order to improve out understanding of the characteristics of swells, this study analysis data collected from a nearshore weather bouy and a coastal wave station. The Wave Watch 3 model is applied with several wind fields, and compared results with that of AVISO. The results show that (1) Waters in southwest of Taiwan, in the northeast monsoon season, the peak wave spectral energy tends to sift from short period to longer period, whereas in the southwest monsoon season, the spectrum of energy varies rapidly and is stronger. During the passage of typhoons, swells from the southern tip of Taiwan show stronger energy in the early stage and weaken gradually, on the other hand, swells from the northern tip of Taiwan show increasing energy spectrum to a peak value. The wave energy diminished after typhoon passed Taiwan Strait. (2) The patterns of wave spectrum are related to the winds. A single peak pattern is usually caused by the local winds. A double peaks wave spectrum suggests both local wind and remote forcing. The lower frequency energy is due to swells. (3) In order to separate the swells from the wind waves in the case of double peaks wave spectrum, two methods are applied. For the no typhoon period, a modified ¡¥P-M spectrum¡¦ is useful as well as is the ¡¥derivative energy spectrum¡¦. For the typhoon period, only the later method provides reasonable results. (4) Based on the analysis of separated wave spectrum, the ratio of occurrence is 65% wind wave and 35% swell in the normal days. The ratio varies during typhoon period. (5) The comparisons of Wave Watch 3 model output with AVISO data suggest that the forcing of QSCAT/NCEP Blended wind provides a better result.

The wind waves have significant effects on small craft and fisheries. Therefore, wind wave climate has an important role in the design and operation of fishing harbors and harbors for small craft. The purpose of this study is to identify the wind wave climate along the eastern part of the Mediterranean Sea coastline of T&uuml / rkiye. For this purpose, wind wave data for a certain period is obtained from ECMWF for the analysis. Moreover, the data will be analyzed for locations selected along the Turkish coast using a special software developed for this thesis study. For every location, the wind wave roses, significant wind wave height versus mean period of primary wind relations, extreme probability distribution, and log-linear cumulative probability distributions will be presented. By the help of software developed, it will be possible to analyse any coordinate using ECMWF data.

In order to meet energy needs in world, studies on wave energy, alternative energy, are becoming more and more important with each passing day. The purpose of this study is to identify the wave energy potential along the coastline of Turkey. For this purpose, the data of wind speed and direction, swell and wind wave height, period and direction for certain duration with the six hours time intervals are obtained from ECMWF for the wind and wave climate computations. In order to compute the wind and wave climate at any selected coastal location, software is developed by Serhan Aldogan in his MSc thesis. By the help of the specifically developed software, for every location, by utilizing existing wind data, depending on geographical location of station, in the direction of energy thought to produce, by using calculated average wind speed of storm which is above the selected wind speed u0, characteristics (Hs / Tm) of the waves of this storm and power (P, W/m) per unit length will be calculated. The duration curves for power, Hs and T, can be obtained. The duration curve represents the occurrence of the parameter (wave height, wave period, wave energy or wave power). It can also be called occurrence curve or availability curve. From these curves, for various percentages of the total storm duration, P, Hs and T&rsquo / s values can be determined. Also, in the analysis, the shapes of these curves can provide important information about the available wave energy for the selected coasts.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18931号 / 工博第3973号 / 新制||工||1612 / 31882 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 間瀬 肇, 教授 平石 哲也, 准教授 森 信人 / 学位規則第4条第1項該当

The sustainable development of the offshore wind and wave energy sectors requires optimising the exploitation of the resources, and it is in relation to this and the shared challenge for both industries to reduce their costs that the option of integrating offshore wind and wave energy arose during the past decade. The relevant aspects of this integration are addressed in this work, and in particular the evaluation of the Wave Energy Converter (WEC) sub-system of a hybrid wind-wave energy converter: the state of the art of combined technologies; the definition of a novel hybrid prototype, based on a preliminary feasibility analysis of a conceptual proposal; and the evaluation of a simplified version of this prototype by means of physical and numerical modelling as a mean to set the reference and define new tools and methods for future evaluation and optimisation of the prototype. Because of the novelty of combined wave and offshore wind systems, fundamental knowledge was lacking as, for example a comprehensive review and classification, which was published as a journal paper framed in the present work. In particular, the core of this PhD thesis deals with the WEC sub-system of a hybrid device that integrates an Oscillating Water Column (OWC) device into the typical monopile substructure of an offshore wind turbine. A new prototype of the hybrid energy converter has been proposed, and a patent application was filled. Furthermore, an experimental set-up was designed, built and tested at a wave flume. On the basis of this experimental campaign the performance of the device is analysed. Finally, a full 3D-numerical mirror of the experimental set-up, including the hybrid energy converter, is defined and validated, and the flume enclosure effects studied for regular waves.

Approved for public release; distribution is unlimited / Capacitance and conductance measurements using two and four wire techniques were developed and statically and dynamically calibrated in this thesis. The voltage sensitivities range from 7.3 to 8.1 ± 0.1 mV/cm for the two wire capacitance system static calibrations. This is ± 5.2% of the limiting theoretical value. The voltage sensitivities range from 0.3 to 0.4 ± 0.1 V/cm for the four wire conductance system static calibrations. Dynamic calibrations were only completed for the conductance system. The dynamic calibration results were weakly frequency dependent with a qj-0.15 decay in a limited, 2-4 Hz range. Wind power spectrum measurements were taken in the existing Upper Ocean Simulations Facility at the Naval Postgraduate School. There was excellent agreement in the spectra with both techniques. Driven gravity wave frequency downshifting and wind energy dumping was observed in the combined gravity wave and wind-wave measurements. The power spectra peaked near two Hertz and decayed at 50 to 70 dB per decade, or as CO -5 to G)" 7 for both systems. Gravity wave phase speed and wavelength measurements were performed with the capacitance system. The results were approximately 40% higher than theory. / http://archive.org/details/developmentcalib00yarb

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18931号 / 工博第3973号 / 新制||工||1612(附属図書館) / 31882 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 間瀬 肇, 教授 平石 哲也, 准教授 森 信人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This study examines wind generated waves during winter storms, their transformation/attenuation near the marsh edge, and the resulting saltmarsh edge erosion. A simple numerical model for wave generation, transmission and marsh edge erosion was developed and validated against observations from Lake Borgne, Louisiana. Results suggest that meteorological conditions modify the local water depth via wind or wave setup and atmospheric pressure, thus exerting a first order control on the location of wave attack, which in turn determines the type of wave forces (shear vs. impact) that dominate the erosion process. Scarp failure follows, at a location determined by water level, creating multiple erosive scarps and terraces. High measured erosion, likely due to marsh edge destabilization followed by subsequent frontal passage forces differential marsh erosion, exposing underlying substrate to further erosion. A conceptual model for marsh edge retreat is developed using these observations and supported further by model predictions.

Winds and wind wave climate are two important phenomena for Black Sea basin. Wind wave climate has an important role on design of coastal structures and naval transportation. Despite this fact the wind wave climate is not well known for the Turkish coasts because of limited studies on this subject. The purpose of the present study was to further understand wind and wind wave climate along the Black Sea coastline of T&uuml / rkiye. For this purpose wind and wind wave data for every 65 months is obtained from ECMWF for and analyzed for 12 locations situated along Black Sea coast of Turkey. For every location the wind [Berk&uuml / n,2007] and wind wave roses, significant wind wave height vs. Mean wave period relations, extreme probability distribution and log-linear cumulative probability distribution are presented. Also a comparison with previous studies is given for better understanding the wind and wave climate better.