Ocean Engineering Commons^™

Containerization Of Seafarers In The International Shipping Industry: Contemporary Seamanship, Maritime Social Infrastructures, And Mobility Politics Of Global Logistics, Liang Wu

Dissertations, Theses, and Capstone Projects

This dissertation discusses the mobility politics of container shipping and argues that technological development, political-economic order, and social infrastructure co-produce one another. Containerization, the use of standardized containers to carry cargo across modes of transportation that is said to have revolutionized and globalized international trade since the late 1950s, has served to expand and extend the power of international coalitions of states and corporations to control the movements of commodities (shipments) and labor (seafarers). The advent and development of containerization was driven by a sociotechnical imaginary and international social contract of seamless shipping and cargo flows. In practice, this liberal, …

Wave Attenuation Capacity Of Suspended Aquaculture Structures With Sugar Kelp And Mussels, Longhuan Zhu

Electronic Theses and Dissertations

Large aquaculture systems may have the potential to damp wave energy for coastal protection. The performance of these systems are influenced by the dynamics of components such as flexible kelp blades and mussel droppers. In this thesis, the dynamics of kelp blades and mussel droppers were investigated with a consistent-mass cable model with focus on understanding the asymmetric motion of kelp blades. The results showed the asymmetric blade motion in symmetric waves is caused by the spatial asymmetry of the encountered wave orbital velocities due to blade displacements and the asymmetric action on the blade by vertical wave orbital velocities. …

Numerical Modeling Of Shoreline Response To Storm Tides And Sea Level Rise, Akash Sahu

Civil & Environmental Engineering Theses & Dissertations

In this study, an integrated hydrodynamic, wave, and sediment transport modeling approach is developed for predicting the spatiotemporal variation of erosion of a sandy shoreline due to storm surge, wave action, tidal variations, and relative sea level rise (RSLR). The study site is located at the northern most portion of the city of Norfolk, Virginia, and it is of importance to the city, both in terms of tourism and for the protection that it provides for upland properties against storms. The region, in general, experiences the highest rate of RSLR on the U.S. East Coast which should result in high …

A Multiline Anchor Concept For Floating Offshore Wind Turbines, Casey Fontana

Doctoral Dissertations

Floating offshore wind turbines (FOWTs) hold great potential for the renewable energy industry, but capital costs remain high. In efforts to increase FOWT substructure efficiency and reduce costs, this thesis investigates a novel multiline anchor concept in which FOWTs share anchors instead of being moored separately. The goal of this thesis is to evaluate the force dynamics, design, and potential cost reduction of the system. Anchor forces are simulated using the NREL 5 MW reference turbine and OC4-DeepCwind semisubmersible platform, and multiline anchor force is computed as the vector sum of the contributing mooring line tensions. The use of a …

An Integrated Closed Convergent System For Optimal Extraction Of Head-Driven Tidal Energy, Michelle Ann Vieira

UNF Graduate Theses and Dissertations

As the demands for energy increased with the global increase in population, there is a need to create and invest in more clean and renewable energy sources. Energy derived from the movement of the tides is an ancient concept that is currently being harnessed in a handful of large tidal range locations. However, the need to move from fossil fuel driven energy sources to those that are clean and non-polluting is a priority for a sustainable future. Globally, hydropower potential is estimated to be more than 16,400-Terawatt hours annually. Given that the electricity consumption worldwide was at 15,068-Terawatt hours in …

Potential Replacement Of The Us Navy's Rapid Penetration Test With The Method Of Multichannel Analysis Of Surface Waves, William Fletcher

UNF Graduate Theses and Dissertations

The United States Navy (USN) currently utilizes a Rapid Penetration Test (RPT) on both land and in water as the means to determine whether sufficient soil bearing capacity exists for piles in axial compression, prior to construction of the Elevated Causeway System (Modular) [ELCAS(M)] pile-supported pier system. The USN desires a replacement for the RPT because of issues with the method incorrectly classifying soils as well as the need to have a less labor-and-equipment-intensive method for geotechnical investigation.

The Multichannel Analysis of Surface Waves (MASW) method is selected herein as the potential replacement for the RPT. The MASW method is …

Transformation Of Nonlinear Waves In The Presence Of Wind, Current, And Vegetation, Haifei Chen

Electronic Theses and Dissertations

Accurate prediction of extreme wave events is crucial for the safe maritime activities and offshore operations. Improved knowledge of wave dissipation mechanisms due to breaking and vegetation leads to accurate wave forecast, protecting life and property along the coast. The scope of the thesis is to examine the wave transformations in the presence of wind, current, and vegetation, using a two-phase flow solver based on the open-source platform OpenFOAM. The Reynolds-Averaged Navier-Stokes (RANS) equations are coupled with a Volume of Fluid (VOF) surface capturing scheme and a turbulence closure model. This RANS-VOF model is adapted to develop a numerical wind-wave-current …

Dns And Les Of Scalar Transfer Across An Air-Water Interface During Inception And Growth Of Langmuir Circulation, Amine Hafsi

USF Tampa Graduate Theses and Dissertations

Direct numerical simulations (DNS) of an initially quiescent coupled air-water interface driven by an air flow with free stream speed of 5 m/s have been conducted. The DNS solves a scalar advection-diffusion equation for dissolved gas (or scalar) concentration in order to determine the impact of the water-side turbulence on scalar (mass) transfer from the air side to the water side and subsequent vertical transport in the water column. Two simulations are compared: one with a freely deforming interface and a second one with a flat interface. In the first simulation, the deforming interface evolves in the form of gravity-capillary …

Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane

Civil & Environmental Engineering Theses & Dissertations

The pace and effects of climate change are an area of constant focus for coastal engineers as evolving patterns in the atmosphere worldwide affect the oceans and coasts on a regional and global scale. Surface waves respond to changing wind patterns both locally and from propagating swell, and the difficulty in predicting future wind patterns is well-established. Expectations that climate change will result in more frequent and intense coastal storms and consequently greater wave heights in the North Atlantic are still unrealized, and recent forecasts from a variety of atmosphere-ocean coupled global climate models instead predict decreasing wave heights through …

Corrosion Protection Systems In Offshore Structures, Hristo Ivanov

Williams Honors College, Honors Research Projects

Corrosion plays a pivotal role in the engineering world. Engineers of all disciplines must consider the dangers that this phenomenon can incur. Interestingly, corrosion mitigation is not a topic that is addressed in most academic curricula. The goal of this paper is to give engineering students a brief introduction into corrosion and some of the prevention techniques commonly used today.

The design of a corrosion protection system for offshore structures is discussed in order to illustrate how these techniques can be utilized even in the most extreme environments. First, the driving force behind corrosion is examined, introducing the basic mechanics …

The Simulation & Evaluation Of Surge Hazard Using A Response Surface Method In The New York Bight, Michael H. Bredesen

UNF Graduate Theses and Dissertations

Atmospheric features, such as tropical cyclones, act as a driving mechanism for many of the major hazards affecting coastal areas around the world. Accurate and efficient quantification of tropical cyclone surge hazard is essential to the development of resilient coastal communities, particularly given continued sea level trend concerns. Recent major tropical cyclones that have impacted the northeastern portion of the United States have resulted in devastating flooding in New York City, the most densely populated city in the US. As a part of national effort to re-evaluate coastal inundation hazards, the Federal Emergency Management Agency used the Joint Probability Method …

Dimensionless Criteria For Selecting Tidally-Influenced Advective-Dispersive Desalination Brine Mixing Plume Characterization Models, Alireza Shahvari

Civil & Environmental Engineering Theses & Dissertations

The very nature of requirements for implementing a desalination process is highly spatial due to the need to secure both a source for the operation and sink for brine dilution. Thus, the applicable coastal location is bound to natural tidal mixing characteristics and subjected to a near- or a far-field availability for source and sink. Mixing characteristics of coastal waters are very different from one point to another due to the spatiotemporal tidal characteristic in loco in a manner that it can vary from being highly advective to completely dispersive dominant. Once a location is identified, estimation of corresponding water …

Aqueous Turbulence Structure Immediately Adjacent To The Air - Water Interface And Interfacial Gas Exchange, Binbin Wang

Theses and Dissertations

Air-sea interaction and the interfacial exchange of gas across the air-water interface are of great importance in coupled atmospheric-oceanic environmental systems. Aqueous turbulence structure immediately adjacent to the air-water interface is the combined result of wind, surface waves, currents and other environmental forces and plays a key role in energy budgets, gas fluxes and hence the global climate system. However, the quantification of turbulence structure sufficiently close to the air-water interface is extremely difficult. The physical relationship between interfacial gas exchange and near surface turbulence remains insufficiently investigated. This dissertation aims to measure turbulence in situ in a complex environmental …

Towards Rans Parameterization Of Vertical Mixing By Langmuir Turbulence In Shallow Coastal Shelves, Nityanand Sinha

USF Tampa Graduate Theses and Dissertations

Langmuir turbulence in the upper ocean is generated by the interaction between the wind-driven shear current and the Stokes drift velocity induced by surface gravity waves. In homogenous (neutrally stratified) shallow water, the largest scales of Langmuir turbulence are characterized by full-depth Langmuir circulation (LC). LC consists of parallel counter-rotating vortices aligned roughly in the direction of the wind. In shallow coastal shelves, LC has been observed engulfing the entire water column, interacting with the boundary layer and serving as an important mechanism for sediment re-suspension.

In this research, large-eddy simulations (LES) of Langmuir turbulence with full-depth LC in a …

The Modified Coastal Storm Impulse Parameter, Sayed Gholamreza Mahmoudpour

Civil & Environmental Engineering Theses & Dissertations

The correlation of the morphological changes to the coast and storm characteristics is among interests of coastal engineers. Better understandings of a storm's potential forces ultimately lead engineers to safer designs and minimize the damages. Therefore, a need to quantify the storm potential forces to a storm parameter is evident. The desired storm parameter is to consider all the relative physical factors and is to present realistic results that then can be proven by actual nature response.

The concept of Coastal Storm Impulse (COSI) parameter was first introduced by Basco and Klentzman (2006) and is based on the conservation of …

Towards The Efficient Probabilistic Characterization Of Tropical Cyclone-Generated Storm Surge Hazards Under Stationary And Nonstationary Conditions, Senanu Kudjo Agbley

Civil & Environmental Engineering Theses & Dissertations

The scarcity of observations at any single location confounds the probabilistic characterization of tropical cyclone-generated storm surge hazards using annual maxima and peaks-over-threshold methods. The EST and the JPM are indirect approaches aimed at estimating the probability distribution of the response variable of interest (i.e. storm surge) using the probability distributions of predictor variables (e.g. storm size, storm intensity etc.). In the first part of this work, the relative performance of the empirical simulation technique (EST; Borgman et al., 1992) and the joint probability method (JPM; Myers, 1970) is evaluated via stochastic simulation methods. It is shown that the JPM …

Laboratory Oxide Coatings: Physical Form And Surface Chemistry, Kea U. Duckenfield

Dissertations, Theses, and Masters Projects

The impact of dissolved trace metals on aquatic ecosystems and human health is controlled by sorption, i.e., binding to the surfaces of environmental particles. Since many environmental particles are coated with highly reactive substances, and since discrepancies in trace metal sorption behavior persist between oxides developed in the laboratory and environmental oxide phases, it was hypothesized that the physical form of oxide coatings may influence the chemical properties of the coated particle. Therefore, relationships between the physical forms of several different Fe(III) oxide coatings and the Cu(II) sorption behavior of the coated solids were investigated in comparison with the component …

The Study Of Wave-Blocking And Current Effects On Nonlinear Interactions Of Shallow-Water Waves Using Advanced Boussinesq Models, Qin Chen

Civil & Environmental Engineering Theses & Dissertations

The first part of this work focuses on the derivation of enhanced Boussinesq-type equations for the combined motion of waves and currents in shallow water areas.

The strategy proposed in this work is to couple two known methods which are the sponge layer concept suitable for short waves and Sommerfeld radiation condition for currents. This coupling method provides satisfactory non-reflective boundaries for the simulation of fully coupled wave/current motion as demonstrated by the numerical experiments. We verify the model against the well known solutions based on the existing theories and good agreement has been observed. The numerical results confirm the …