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Ocean Engineering Commons™

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2019

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Articles 31 - 55 of 55

Full-Text Articles in Ocean Engineering

Advancing Numerical Calculation Of Mixed Sized Sediment Transport And Morphology Change, Irene Margaret Watts Jul 2019

Advancing Numerical Calculation Of Mixed Sized Sediment Transport And Morphology Change, Irene Margaret Watts

Theses and Dissertations

Numerical modeling of sediment transport and morphologic change has become a powerful tool for studying and working in the coastal zone. Numerical calculation can assist in a broad range of projects from regional sediment management to beach nourishment as well as evaluating environmental aspects of dredging and placement and implications to water quality and turbidity. Success in application of these tools is partially dependent on the quality of characterization of the sediments in the field. These parameters could include grain size, mineralogical composition, specific gravity and fall velocity. Sediment transport formulations are sensitive to the spatial representation of the sediments …

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A Coastal Estuarine Ensemble Forecasting System, Peyman Taeb Jul 2019

A Coastal Estuarine Ensemble Forecasting System, Peyman Taeb

Theses and Dissertations

This research has been conducted in an effort to reduce the computational costs associated with high-resolution coastal estuarine modeling in ADCIRC. It was proposed that model scalability will be significantly enhanced if the conventional single-domain technique is replaced by a nesting method. Preliminary testing indicated the potential for 50% to more than 80% simulation runtime reduction (depending on the study site) by implementing a nesting technique. Once the concept was proved, the development of an operational, ensemble-based forecasting system, exclusively for the east coast of Central Florida and the IRL system, was implemented. The system, referred to as Ensemble Multistage, …

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The Effect Of Hydro-Meteorology On Ship Collision Avoidance In Heavy Traffic Areas With A Simplified Simulation Model, Ming-Chung Fang, Kun-Yuan Tsai, Chih-Chung Fang Jun 2019

The Effect Of Hydro-Meteorology On Ship Collision Avoidance In Heavy Traffic Areas With A Simplified Simulation Model, Ming-Chung Fang, Kun-Yuan Tsai, Chih-Chung Fang

Journal of Marine Science and Technology–Taiwan

On the basis of the ship collision avoidance steering system in calm water developed by the authors, this paper upgrades the numerical simulation model by considering various hydrometeorological factors for ships with nonuniform movement. A real-time simulator was used for the numerical simulation of the container ship. To clarify the validity of the maneuvering mathematical model, sea trial results for the container ship were compared with the results for the present simulation system in terms of turn trajectory. In this study, a numerical technique based on Nomoto’s second-order model was employed to investigate the turning characteristics of a container ship. …

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Identifying Nonlinear Oscillators By An Energetic Functional In The Linear Space Of Temporal Boundary Functions, Chein-Shan Liu, Yung-Wei Chen, Jiang-Ren Chang Jun 2019

Identifying Nonlinear Oscillators By An Energetic Functional In The Linear Space Of Temporal Boundary Functions, Chein-Shan Liu, Yung-Wei Chen, Jiang-Ren Chang

Journal of Marine Science and Technology–Taiwan

We resolve the inverse problems of a second-order nonlinear oscillator to recover time-dependent damping function and nonlinear restoring force, with the help of temporal boundary data measured at initial time and final time. By using these data, a sequence of temporal boundary functions of time is derived, which satisfy the measured temporal boundary conditions automatically, and are at least the fourth-order polynomials of time. All the temporal boundary functions and zero element constitute a linear space, and a new concept of energetic functional is introduced in the linear space, of which the energy is preserved for each energetic temporal boundary …

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Membrane Hull Technology Implemented Into A D-Collar Work Boat, Joshua Hagan May 2019

Membrane Hull Technology Implemented Into A D-Collar Work Boat, Joshua Hagan

Theses and Dissertations

Membrane Hull Technology (MHT) was initially developed for the United States Navy Rigid-Hull Inflatable Boats (RHIB) as an alternative structure design to provide weight savings and shock mitigation. MHT accomplishes this by veering away from traditional hull design and utilizing a grid like system with an increased number of longitudinal stringers and transverse frames with a significantly lower moment of inertia when compared to traditional stringers and bulkheads. The decrease in stiffness allows for increased deflection in the hull during high load events with the added benefit of shock absorption. This technology, developed by Structural Composites Inc., has been successfully …

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Experimental And Numerical Analysis Of The Drag Force On Surfboards With Different Shapes, Omar Lahlou May 2019

Experimental And Numerical Analysis Of The Drag Force On Surfboards With Different Shapes, Omar Lahlou

Theses and Dissertations

The aim of the present study is to define the hydrodynamic resistance of surfboards with different designs. Decreasing the drag acting on a board helps the surfer to attain higher surfing performances. It helps to attain higher speeds and maneuvering for the surfer. In this thesis, theoretical, experimental and computational approaches are used to explain how the drag changes with different surfboard shapes. Four surfboards with varying shapes were towed at different speeds and the resulting force was recorded. Two computational models were developed using Star CCM and Flowsquare to confirm the experimental results. The drag force on the boards …

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Feasibility Study And Hydrodynamics Of Transformable Submersible Hydrofoil Trimaran, Yipeng Pan May 2019

Feasibility Study And Hydrodynamics Of Transformable Submersible Hydrofoil Trimaran, Yipeng Pan

Theses and Dissertations

It has been the endeavor of naval architects to design innovative hull forms to address the political, socio-economic climate and sustainability around the world. It is imperative that countries be able to protect their sea lanes and coastal zones from surveillance and infiltration from hostile foreign entities. Hence there is a need to develop radically different hull form, which possess the elusive ability and are capable of high-speed. In order to fulfill the idea, the hypothesis envisioned in this thesis is: the Transformable Submersible Hydrofoil Trimaran (TSHT) as an innovative and ground breaking hull form would address the feasibility of …

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Cavitation Number As A Function Of Disk Cavitator Radius: A Numerical Analysis Of Natural Supercavitation, Reid Prichard Apr 2019

Cavitation Number As A Function Of Disk Cavitator Radius: A Numerical Analysis Of Natural Supercavitation, Reid Prichard

Senior Honors Theses

Due to the greater viscosity and density of water compared to air, the maximum speed of underwater travel is severely limited compared to other methods of transportation. However, a technology called supercavitation – which uses a disk-shaped cavitator to envelop a vehicle in a bubble of steam – promises to greatly decrease skin friction drag. While a large cavitator enables the occurrence of supercavitation at low velocities, it adds substantial unnecessary drag at higher speeds. Based on CFD results, a relationship between cavitator diameter and cavitation number is developed, and it is substituted into an existing equation relating drag coefficient …

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Experimental Study Of Scour Around Monopile And Jacket-Type Offshore Wind Turbine Foundations, Hsin-Hung Chen Apr 2019

Experimental Study Of Scour Around Monopile And Jacket-Type Offshore Wind Turbine Foundations, Hsin-Hung Chen

Journal of Marine Science and Technology–Taiwan

Wind turbines platforms and pillars on offshore wind farms are negatively affected by wave and current action. In Taiwan, the water depth of most planned wind turbine foundations is more than 15 m. At this water depth, scour around offshore wind turbine foundations is mainly subject to the ocean current, which causes damage or collapse of foundations. Therefore, this study focused on the influence of ocean current on the monopile and jacket-type foundations of offshore wind turbines. Hydraulic model experiments were conducted to investigate the maximum scour depth and range around pillars in these foundations. Under the effects of current, …

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Wavelet Transform On Digital Rainbow Hologram Based On Spectral Compression For Quality Enhancement In 3d Display Media, Ucuk Darusalam, Panca Dewi Pamungkasari Apr 2019

Wavelet Transform On Digital Rainbow Hologram Based On Spectral Compression For Quality Enhancement In 3d Display Media, Ucuk Darusalam, Panca Dewi Pamungkasari

Makara Journal of Technology

A digital rainbow hologram (DRH) is a potential next-generation three-dimensional display media for the development of modern and smart electronics devices. It is one of the methods that can support the characteristic whereby a realistic display media occupies the space that the real object would have occupied. Since a rainbow hologram records a large amount of spatial or temporal frequency component from the object that represents the rainbow spectrum, a large amount of information needs to be decoded digitally. In this paper, to reconstruct a DRH, we propose a novel method based on the modulation of red, green, and blue …

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Data Fusion Method Based On Adaptive Kalman Filtering, Bernadus Herdi Sirenden Apr 2019

Data Fusion Method Based On Adaptive Kalman Filtering, Bernadus Herdi Sirenden

Makara Journal of Technology

This paper discusses data fusion methods to combine the data from a rotary encoder and ultrasonic sensor. Both sensors are used in a micro-flow calibration system developed by the Research Center of Metrology LIPI. The methods studied are hierarchical data fusion and Kalman filtering. Three types of Kalman filters (KFs) are compared: the conventional Kalman filter and two adaptive Kalman filters. Moreover, a method to combine the uncertainty results from KF in hierarchical data fusion is proposed. The aim of this study is to find appropriate methods of data fusion that can be implemented in micro-flow calibration systems. Data from …

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Molecularly Conductive Behavior Of Blended Polymer Electrolyte-Based Cmc/Pva, Noor Saadiah Mohd Ali, Dishen Zhang, Yuki Nagao, Ahmad Salihin Samsudin Apr 2019

Molecularly Conductive Behavior Of Blended Polymer Electrolyte-Based Cmc/Pva, Noor Saadiah Mohd Ali, Dishen Zhang, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

This study investigated the electrical conduction and structural behavior of blended polymer electrolyte (BPE)-based carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) in the development of solid-state electrochemical devices. Based on impedance spectroscopy and correlating Fourier transform infrared (FTIR) with thermogravimetric analysis, a framework was proposed to explain the structural enhancement of the BPE system. As revealed by FTIR, the optimum conductivity of CMC/PVA BPEs was 9.21 × 10−6 Scm−1 for 80:20 composition attributed to the intermolecular attraction between the polymers. Thermal stability of the CMC/PVA was influenced by the formation of a hydrogen bond between the hydroxyl (-OH), carboxylate (-COO-), …

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Multistage Sonication Effect On The Composition And Properties Of Degraded Chitosan Product, Nurul Laili Arifin, Emma Savitri, Anjar Indah, Fesa Putra, Sumarno Sumarno Apr 2019

Multistage Sonication Effect On The Composition And Properties Of Degraded Chitosan Product, Nurul Laili Arifin, Emma Savitri, Anjar Indah, Fesa Putra, Sumarno Sumarno

Makara Journal of Technology

The sonication method randomly breaks polymer chains to produce a varied distribution of products. A scheme with multi-stage sonication steps is proposed to identify oligomers and low molecular weight chitosan based on changes to the degrad-ed product. For each sonication level, 1% (w/v) chitosan in 1% (v/v) aqueous acetic acid was sonicated for 120 min at 60 °C. The products of the sonication treatment were deprotonized by adding an alkali solution, freeze dried and insoluble product re-sonicated until a low molecular weight was produced. Low molecular weight chitosan/insoluble products were character-ized with Fourier-transform infrared spectra (FT-IR) and X-ray diffraction (XRD) …

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Study Of Zno Nanospheres Fabricated Via Thermal Evaporation For Solar Cell Application, Fatin Farisha Alia Azmi, Bouchta Sahraoui, Saifful Kamaluddin Muzakir Apr 2019

Study Of Zno Nanospheres Fabricated Via Thermal Evaporation For Solar Cell Application, Fatin Farisha Alia Azmi, Bouchta Sahraoui, Saifful Kamaluddin Muzakir

Makara Journal of Technology

A solar cell is a device that absorbs light energy to generate electrical energy. A typical example of a solar cell is the quantum dot solar cell (QDSC), which consists of three main components: (i) fluorophore: the component that absorbs light and generates excited state electrons and holes, (ii) photoelectrode: the component that transports the excited state electron and prevents recombination of excited state electrons and holes, and (iii) electrolyte: the component that re-plenishes the vacancy left by the excited electron in the hole. Despite the increasing number of research in the QDSC field, to date, a device with significant …

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Sorption-Based Energy Storage Systems: A Review, Kyaw Thu, Nasruddin Nasruddin, Sourav Mitra, Bidyut Baran Saha Apr 2019

Sorption-Based Energy Storage Systems: A Review, Kyaw Thu, Nasruddin Nasruddin, Sourav Mitra, Bidyut Baran Saha

Makara Journal of Technology

Mismatched timing between the supply and demand of energy calls for reliable storage systems. Energy storage systems have become further significant with the widespread implementation of renewable energy. These systems can mitigate problems that are often associated with renewable energy sources such as supply unreliability while meeting the de-mand during peak hours. Energy can be stored in various forms, yet storage systems can be generally grouped based on their output forms, namely (i) electricity and (ii) heat or thermal energy. Electrical energy is the most convenient and effective form since it can power almost all modern devices. However, the electricity …

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Electrical Properties Of A Novel Solid Biopolymer Electrolyte Based On Algi-Nate Incorporated With Citric Acid, Ahmad Faizrin Ahmad Fuzlin, Noor Syahida Ismail, Yuki Nagao, Ahmad Salihin Samsudin Apr 2019

Electrical Properties Of A Novel Solid Biopolymer Electrolyte Based On Algi-Nate Incorporated With Citric Acid, Ahmad Faizrin Ahmad Fuzlin, Noor Syahida Ismail, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

In the present study, a novel solid biopolymer electrolyte (SBE) system is introduced by doping citric acid into alginate polymer. A sample of the alginate-citric acid SBE system was prepared via a solution casting technique. Using electrical impedance spectroscopy (EIS), the electrolytes of alginate-citric acid analyzed from 5 Hz to 1 MHz achieved the highest conductivity at 20 wt.% of 5.49 × 10-7 S cm-1. The temperature dependence of various citric acid amounts obeyed the Arrhenius rule with R2~1, where all SBE systems were thermally activated with increasing temperature. The dielectric studies of the alginate-citric acid SBE system showed non-Debye …

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Numerical Study On Seakeeping Performance Of Hydrofoil Assisted Submersible Trimaran (Hast), Yuchen Lin Mar 2019

Numerical Study On Seakeeping Performance Of Hydrofoil Assisted Submersible Trimaran (Hast), Yuchen Lin

Theses and Dissertations

The present study focuses on the seakeeping characteristics of Hydrofoil Assisted Submersible Trimaran (HAST). The seakeeping performance is an important part in ship design because it effects the comfort, control, resistance and safety. The motions in wave will reduce the performance of ship which is designed and optimized in calm water. The heave and pitch motions of HAST in calm water and regular waves have been investigated by STAR CCM+, a CFD analysis program. The theory of numerical simulation based on STAR CCM+ has been presented. The basic theory of seakeeping performance studies has been discussed. A series of simulations …

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Closed Loop Energy Maximizing Control Of A Wave Energy Converter Using An Estimated Linear Model That Approximates The Nonlinear Froude-Krylov Force, Yaqzan Mohd Yaqzan Jan 2019

Closed Loop Energy Maximizing Control Of A Wave Energy Converter Using An Estimated Linear Model That Approximates The Nonlinear Froude-Krylov Force, Yaqzan Mohd Yaqzan

Dissertations, Master's Theses and Master's Reports

Wave energy converters (WECs) exploit ocean wave energy and convert it into useful forms such as electricity. But for WECs to be successful on a large scale, two primary conditions need to be satisfied. The energy generated must satisfy the network requirements, and second, energy flow from waves to the grid needs to be maximized. In this dissertation, we address the second problem. Most control techniques for WECs today use the Cummins' linear model to simulate WEC hydrodynamics. However, it has been shown that under the application of a control force, where WEC motions are amplified, the linear model diverges …

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Development Of A Fused Deposition 3d Printed Buoy And Method For Quantifying Wave Tank Reflections, Samantha G. Swartzmiller Jan 2019

Development Of A Fused Deposition 3d Printed Buoy And Method For Quantifying Wave Tank Reflections, Samantha G. Swartzmiller

Dissertations, Master's Theses and Master's Reports

Testing model scale prototypes is integral to the development of wave energy converter (WEC) technology. Model scale WECs are tested in wave tanks where they are subjected to repeatable wave fields. Their presence in water creates radiated waves that eventually reflect off tank walls disrupting the intended wave field. Fabrication of model scale WECs is another developing aspect of tank testing. Often model WECs are built of foam. Additive manufacturing is a promising alternative although the most common method, fused deposition modeling (FDM) 3D printing, does not typically produce waterproof parts. The goals of this work were 1) develop a …

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Optimization And Control Of Arrays Of Wave Energy Converters, Jianyang Lyu Jan 2019

Optimization And Control Of Arrays Of Wave Energy Converters, Jianyang Lyu

Dissertations, Master's Theses and Master's Reports

Wave Energy Converter Array is a practical approach to harvest ocean wave energy. To leverage the potential of the WEC array in terms of energy extraction, it is essential to have a properly designed array configuration and control system. This thesis explores the optimal configuration of Wave Energy Converters (WECs) arrays and their optimal control. The optimization of the WEC array allows both dimensions of individual WECs as well as the array layout to varying. In the first optimization problem, cylindrical buoys are assumed in the array where their radii and drafts are optimization parameters. Genetic Algorithms are used for …

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Examination Of Ice Impactor And Mold, Matt Wilson Jan 2019

Examination Of Ice Impactor And Mold, Matt Wilson

Williams Honors College, Honors Research Projects

This research project investigates impact and damage response of composite sandwich structures impacted with solid ice at extreme low-temperature. Composite sandwich structures of carbon fiber reinforced polymer sheets lining a polyvinyl chloride foam core are subjected to low-velocity impact at arctic temperatures. This impact will be delivered by a solid ice tool-tip via a drop impact testing machine. Data and test results acquired will be composed into a research report that will be submitted to The University of Akron and published in a scientific journal. This project builds upon the earlier study by Elamin, Li, & Tan (2018).

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Surf Zone Tilt Current Meter, Troy Heitmann Jan 2019

Surf Zone Tilt Current Meter, Troy Heitmann

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Coastal tides and free surface gravity waves locally interact with the nearshore bathymetry generating spatially diverse circulation cells. Collectively, the cells form a current velocity flow field where net transport of geological, chemical, or biological, particulates takes place. Within the surf zone, dynamic instabilities lead to chaotic evolution and mixing, where single point, observations fail to quantitatively char­acterize the system as a whole. Governed by advanced theories, numerical models provide the necessary sampling resolution to study surf zone processes over large do­mains, but the model must be validated with field observations to draw meaningful conclusions. The acoustic Doppler current profiler …

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Developing In Situ Dissolved Inorganic Carbon Dioxide Instrumentation, Beckett Colson Jan 2019

Developing In Situ Dissolved Inorganic Carbon Dioxide Instrumentation, Beckett Colson

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

The ocean carbon system plays a critical role in regulating carbon dioxide content in the atmosphere. With increased anthropogenic carbon input, it is even more important to understand the system through measurements, models, and predictions. Unfortunately, the spatiotemporal resolution of ocean carbon system measurements is limited by a lack of in situ instrumentation. The support of the Link Foundation Ocean Engineering and Instrumentation Fellowship has enabled me to make significant progress in developing an in situ carbon system instrument for the deep sea. The instrument will measure both total dissolved inorganic carbon (DIC) and the partial pressure of carbon dioxide …

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Link Foundation Fellowship Report, Eric Nieves Jan 2019

Link Foundation Fellowship Report, Eric Nieves

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Magnetic anomaly detection (MAD) is a leading technique for the detection and localization of obscured magnetic targets via exploiting the field anomalies they create. This is especially true in marine environments when looking for unexploded ordnance (UXO), because the DC magnetic field is not highly influenced by numerous types of media (i.e. water) or weather conditions. MAD is also a passive technique, which allows it to go unnoticed by the target. Whereas current applications of MAD have been shown to be effective for localizing single targets at a time, the development of a method for multiple localization would the robustness …

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The Tides They Are A-Changin’: A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms And Future Implications, Ivan D. Haigh, Mark D. Pickering, J.A. Mattias Green, Brian K. Arbic, Arne Arns, Soenke Dangendorf, David Hill, David A. Jay, Multiple Additional Authors Jan 2019

The Tides They Are A-Changin’: A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms And Future Implications, Ivan D. Haigh, Mark D. Pickering, J.A. Mattias Green, Brian K. Arbic, Arne Arns, Soenke Dangendorf, David Hill, David A. Jay, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

Scientists and engineers have observed for some time that tidal amplitudes at many locations are shifting considerably due to non-astronomical factors. Here we review comprehensively these important changes in tidal properties, many of which remain poorly understood. Over long geological time-scales, tectonic processes drive variations in basin size, depth, and shape, and hence the resonant properties of ocean basins. On shorter geological time-scales, changes in oceanic tidal properties are dominated by variations in water depth. A growing number of studies have identified widespread, sometimes regionally-coherent, positive and negative trends in tidal constituents and levels during the 19th, 20th and early …

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