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Journal of Marine Science and Technology–Taiwan

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Full-Text Articles in Engineering

Effect Of Battery Energy Storage Systems On The Value Of An Intermittent Wind Energy Source In Isolated Systems, Chun-Lung Chen Apr 2016

Effect Of Battery Energy Storage Systems On The Value Of An Intermittent Wind Energy Source In Isolated Systems, Chun-Lung Chen

Journal of Marine Science and Technology–Taiwan

The increase in environmental protection awareness and the progressive exhaustion of conventional fossil energy sources have increased interests in integrating wind energy sources into existing power systems. Despite the various benefits of wind power, the intermittency and unpredictability of wind power generation cause operational concerns and waste usable capacity as the installation of the wind generation sources increases. To enhance the value of an intermittent wind energy source by using a battery energy storage system (BESS), an iterative algorithm that combines improved dynamic programming and a hybrid direct search method were developed for solving the optimal wind-thermal-battery coordination scheduling (WTBCS) …

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Hydraulic System Design And Structural Analysis Of A Bop Gantry Crane, Hyun-Ji Kim, Gwi-Nam Kim, Chang-Kweon Jeong, Young-Hwan Yoon, Yong-Gil Jung, Sun-Chul Huh Apr 2016

Hydraulic System Design And Structural Analysis Of A Bop Gantry Crane, Hyun-Ji Kim, Gwi-Nam Kim, Chang-Kweon Jeong, Young-Hwan Yoon, Yong-Gil Jung, Sun-Chul Huh

Journal of Marine Science and Technology–Taiwan

A blowout preventer (BOP) gantry crane is an offshore plant that moves a BOP stack located on a drilling platform to a BOP trolley. However, such a plant has yet to be developed in Korea. Because BOP gantry cranes produced overseas are expensive, developing such cranes domestically is imperative. In this study, ANSYS was used to conduct a structural analysis on a BOP gantry crane model to simulate the roll and pitch motions of a drillship that were induced by waves and wind load as well as the weight of the crane. Moreover, Simulation X was used for implementing control-system …

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Using Principal Component Analysis With A Back-Propagation Neural Network To Predict Industrial Building Construction Duration, Sou-Sen Leu, Chi-Min Liu Apr 2016

Using Principal Component Analysis With A Back-Propagation Neural Network To Predict Industrial Building Construction Duration, Sou-Sen Leu, Chi-Min Liu

Journal of Marine Science and Technology–Taiwan

Industrial businesses must respond efficiently to market demands; therefore, industrial construction must accurately predict the project duration at the pre-investment stage. In practice, project duration predictions rely on the experience of project managers. To provide impartial expertise and quantitative estimate the predicted duration of constructing an industrial building, an extensive history of industrial building cases were collected to form a database. Principal component analysis was applied to the database to identify key factors to serve as input data for a back-propagation neural network (BP-NN) that was used to estimate the project duration. Three prediction models were identified and developed separately …

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Carbonation Resistance Of Concrete With Mortar Coating, Wen-Hu Tsao, Ming-Te Liang, Nai-Ming Huang, Ke-Hung Liao Apr 2016

Carbonation Resistance Of Concrete With Mortar Coating, Wen-Hu Tsao, Ming-Te Liang, Nai-Ming Huang, Ke-Hung Liao

Journal of Marine Science and Technology–Taiwan

The principal purpose of this paper was theoretically to study the carbonation resistance of a semi-infinite medium which concrete has a mortar coating having diffusion properties different from those of the rest of the medium. The analytical solution of a semi-infinite composite medium was used to predict the time required for subsidence due to concrete with mortar coating. The inaccurate analytical solution was published in previous books. Thus, the analytical solution of a semi-infinite composite medium is re-derived in this article. The governing equations without initial and boundary conditions in the previous books are also pointed out. In order to …

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Effect Of Cooling Rate During Solution Heat Treatment On The Microstructure And Mechanical Properties Of Sp-700 Titanium Alloys, Jo-Kuang Nieh, Chih-Ting Wu, Yen-Lin Chen, Chao-Nan Wei, Sheng-Long Lee Apr 2016

Effect Of Cooling Rate During Solution Heat Treatment On The Microstructure And Mechanical Properties Of Sp-700 Titanium Alloys, Jo-Kuang Nieh, Chih-Ting Wu, Yen-Lin Chen, Chao-Nan Wei, Sheng-Long Lee

Journal of Marine Science and Technology–Taiwan

The relationship between the microstructures and the mechanical properties of solution-treated SP-700 titanium alloys, as obtained with different cooling rates, was investigated. The results indicate that the water-quenched alloy contains the primary  (p), ”-martensite and residual  (r) phases. Aging heat treatment can convert both ”-martensite and the r phases to the fine-grained  +  equilibrium phases, resulting in a significant increase in tensile strength and hardness. Both the air-cooled and furnace-cooled alloys consist of the p,  and  phases. The air-cooled alloy containing the fine-grained  phase has relatively higher hardness. Aging heat treatment causes only …

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Side Friction Of Drilled Piles In Cobble Layers, Tien-Kuen Huang, Chih-Yi Yang Apr 2016

Side Friction Of Drilled Piles In Cobble Layers, Tien-Kuen Huang, Chih-Yi Yang

Journal of Marine Science and Technology–Taiwan

Full scale vertical load tests have been carried out on drilled piles in cobble layers to evaluate side friction capacity. In the finite element analysis, firstly the property of pile is assumed linear elastic and the elastic-plastic Mohr-Coulomb model is used for the cobble layer. Interface elements are introduced to model interface interaction between pile and cobble layer. The measured data obtained from the field tests are compared with the finite element simulation results using PLAXIS 2D. It shows reasonable agreement between field test data and simulation results. A preliminary evaluation of side friction of drilled piles in cobble layers …

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Maximum-Likelihood Directivity For Depicting Perceptual Contours, Chun-Shun Tseng, Jung-Hua Wang, Ren-Jie Huang Apr 2016

Maximum-Likelihood Directivity For Depicting Perceptual Contours, Chun-Shun Tseng, Jung-Hua Wang, Ren-Jie Huang

Journal of Marine Science and Technology–Taiwan

This paper presents a novel method based on MaximumLikelihood Estimation (MLE) to evaluate pixel directivity for depicting image contours of objects as perceived by human eyes. The method is characterized by employing discrete masks with different shapes centered at a target pixel to sample gradient orientations of neighboring pixels for evaluating directivity of the target pixel, and applying MLE to determine one of these discrete sampling masks that best fits the orientation similarity of the target pixel. We show that such a fitting process in effect fulfils the similarity and proximity laws in Gestalt theory, and a salient alignment location …

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Efficiently Mining Frequent Itemsets In Transactional Databases, Salah Alghyaline, Jun-Wei Hsieh, Jim Z. C Lai Apr 2016

Efficiently Mining Frequent Itemsets In Transactional Databases, Salah Alghyaline, Jun-Wei Hsieh, Jim Z. C Lai

Journal of Marine Science and Technology–Taiwan

Discovering frequent itemsets is an essential task in association rules mining and it is considered to be computationally expensive. To find the frequent itemsets, the algorithm of frequent pattern growth (FP-growth) is one of the best algorithms for mining frequent patterns. However, many experimental results have shown that building conditional FP-trees during mining data using this FP-growth method will consume most of CPU time. In addition, it requires a lot of space to save the FP-trees. This paper presents a new approach for mining frequent item sets from a transactional database without building the conditional FP-trees. Thus, lots of computing …

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The Study On The Non-Linear Dynamic Causal Relationships Between Construction Index And Its Materials Indexes, Yih-Chang Wang, Ran Huang, Chien-Chung Nieh, Tsai-Lung Weng Apr 2016

The Study On The Non-Linear Dynamic Causal Relationships Between Construction Index And Its Materials Indexes, Yih-Chang Wang, Ran Huang, Chien-Chung Nieh, Tsai-Lung Weng

Journal of Marine Science and Technology–Taiwan

This paper aims to examine the short-run and long-run nonlinear dynamic relationship between indexes of construction and cement or steel in the Taiwan stock markets over the 1995- 2011 periods. In addition to traditional linear co-integration tests, the threshold co-integration and asymmetric threshold error-corrrection models (TECM) suggested by Enders and Siklos (2001) are used. Linear co-integration tests reveal no co-integration between the construction index and either of the cement and steel indexes, while threshold co-integration tests show existence of the co-integration relationship and asymmetric adjustment. Further analysis from TECM Granger causality tests finds evidence of a bi-directional causality between cement …

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Establishment Of Effective Metamodels For Seakeeping Performance In Multidisciplinary Ship Design Optimization, Dongqin Li, Philip A Wilson, Xin Zhao Apr 2016

Establishment Of Effective Metamodels For Seakeeping Performance In Multidisciplinary Ship Design Optimization, Dongqin Li, Philip A Wilson, Xin Zhao

Journal of Marine Science and Technology–Taiwan

Ship design is a complex multidisciplinary optimization process to determine configuration variables that satisfy a set of mission requirements. Unfortunately, high fidelity commercial software for the ship performance estimation such as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) is computationally expensive and time consuming to execute and deters the ship designer’s ability to explore larger range of optimization solutions. In this paper, the Latin Hypercube Design was used to select the sample data for covering the design space. The percentage of downtime, a comprehensive seakeeping evaluation index, was also used to evaluate the seakeeping performance within the short-term …

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Evaluation Of Penetration Depth And Protective Effectiveness Of Concrete-Penetrating Sealer Materials, Sung-Ching Chen, Ran Huang, Hui-Mi Hsu, Si-Yu Zou, Li-Wei Teng Apr 2016

Evaluation Of Penetration Depth And Protective Effectiveness Of Concrete-Penetrating Sealer Materials, Sung-Ching Chen, Ran Huang, Hui-Mi Hsu, Si-Yu Zou, Li-Wei Teng

Journal of Marine Science and Technology–Taiwan

Crystal penetrating sealer materials (PSMs) are commonly used on the surface of concrete to protect the surface from damage and thereby extend its service life. Such materials penetrate into existing pores or cracks and form crystals, which block potential paths through which unknown materials could enter and degrade the concrete. In this study, the constituent compounds of a PSM were divided into seven categories, labeled CAT I to CAT VII, and five discrete particle size fractions corresponding to sieve Nos. 30, 50, 100, 200, and 200 were considered. Energy dispersive spectrometry revealed that the constituent elements of the PSM were …

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Model Tests Of Dragging Hall Anchors In Sand, Yu-Xiao Ren, Zhen-Ming Lei, Li-Qiang Sun, Shu-Wang Yan Feb 2016

Model Tests Of Dragging Hall Anchors In Sand, Yu-Xiao Ren, Zhen-Ming Lei, Li-Qiang Sun, Shu-Wang Yan

Journal of Marine Science and Technology–Taiwan

Hall anchors are often used as the main anchors in great medium ships. However, the methods for determining the holding capacity of Hall anchors when being pulled in soil are rarely proposed. In this study, a series of model tests was carried out using four scaled Hall anchor models to determine the kinematic behavior, trajectory, and development rules of the holding capacity of the anchors relative to dragging distances. Moreover, the holding force coefficients of the Hall anchors in sand were identified after the tests

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Methods For Designing Partially Inflated Geotubes, Shu-Wang Yan, Jing Chen, Li-Qiang Sun Feb 2016

Methods For Designing Partially Inflated Geotubes, Shu-Wang Yan, Jing Chen, Li-Qiang Sun

Journal of Marine Science and Technology–Taiwan

A widely used technique in constructing dikes for land reclamation is to use tubes made of sewn geosynthetic sheets. These tubes are usually filled with slurry comprising soils, such as sand, silt, and clay. The tension stress that develops in geosynthetic tubes during tube filling is the dominant factor considered in constructing safe dikes. Existing design methods are effective for sausage-shaped tube designs; however, they cannot be directly applied in flat tubes, which are commonly used in dike construction. This paper presents a procedure that can determine the relationships among tube size, pumping pressure, unit weight of the slurry, and …

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Mechanism And Model Testing Of Pipelay Vessel Roll Affected By Large Period Swells, Jia Li, Zhen-Ming Lei, Li-Qiang Sun, Shu-Wang Yan Feb 2016

Mechanism And Model Testing Of Pipelay Vessel Roll Affected By Large Period Swells, Jia Li, Zhen-Ming Lei, Li-Qiang Sun, Shu-Wang Yan

Journal of Marine Science and Technology–Taiwan

Pipelay vessels, such as the Hai Yang Shi You 201, have been seriously affected by large period swells in the East China Sea, where the roll amplitude is extremely large for normal pipe lay. Two conditions that can generate dramatic rolls, namely, parametric and synchronous rolling, were analyzed theoretically in this study. Model tests were also performed on the pipelay vessel Hai Yang Shi You 201 with course angles of 0, 30, 60, and 90°in swells of varying periods and wave heights to examine the aforementioned effect. The test data proved that drastic roll is not caused by parametric rolling, …

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Pore Pressure Characteristics In Isotropic Consolidated Saturated Clay Under Unloading Conditions, Shu-Wang Yan, Jing-Jing Zhang, Ying-Hui Tian, Li-Qiang Sun Feb 2016

Pore Pressure Characteristics In Isotropic Consolidated Saturated Clay Under Unloading Conditions, Shu-Wang Yan, Jing-Jing Zhang, Ying-Hui Tian, Li-Qiang Sun

Journal of Marine Science and Technology–Taiwan

When foundations, such as caissons, spudcans, and mudmats, are pulled out from the saturated soft clay foundation, negative excess pore pressure will develop in the interface between the base and the soil. This phenomenon will significantly increase the uplift force. Therefore, estimating the developed negative excess pore pressure in the interface under unloading conditions is important. The development of excess pore pressure was investigated based on the triaxial extension test under isotropic consolidation condition. The method of using the modified Cambridge model to predict the excess pore pressure was programmed and has been proven to be feasible. By associating Henkel’s …

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Multi Agv Scheduling Problem In Automated Container Terminal, Jian Jin, Xiao-Hua Zhang Feb 2016

Multi Agv Scheduling Problem In Automated Container Terminal, Jian Jin, Xiao-Hua Zhang

Journal of Marine Science and Technology–Taiwan

In this paper we propose a dynamic multi automated guided vehicle (AGV) scheduling method based on the scheduling properties of automated container terminal handling systems. In multi-AGV scheduling, the composition of AGV handling time and the precedence order of certain tasks are major constraints. Taking these into consideration, we design a genetic algorithm (GA) for a dynamic multi-AGV scheduling model to minimize completion time and standard deviation of handling time of quay cranes (QC), and validated the proposed model through numerical experiment. We expect this model to be significant for multi-agent scheduling of discrete production systems.

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Deployment Approach To Nodes Of The Iot For Monitoring Systems In Ports, Yang-Yang Hao, Yi Wu, Bin Yang, You-Fang Huang Feb 2016

Deployment Approach To Nodes Of The Iot For Monitoring Systems In Ports, Yang-Yang Hao, Yi Wu, Bin Yang, You-Fang Huang

Journal of Marine Science and Technology–Taiwan

In order to solve the conflict between higher monitoring quality and lower application costs of the internet of the things (IoT) monitoring system in ports, a mixed integer non-linear programming model was built. Various key factors, such as network scale, cost, representation level, and the deployment of nodes for the balance degree of the IoT, are comprehensively taken into consideration in this programming model. Furthermore, the quantity and deployment solution was solved through a genetic algorithm; in addition, the selection of nodes was evaluated. Simulation results show that the deployment solution is conducive to solve the quality-cost conflict to some …

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Anti-Windup Schemes For Nonlinear Active Disturbance Rejection Control In Marine Steam Turbine, Yuan-Qing Wang, Guang Ren, Jun-Dong Zhang Feb 2016

Anti-Windup Schemes For Nonlinear Active Disturbance Rejection Control In Marine Steam Turbine, Yuan-Qing Wang, Guang Ren, Jun-Dong Zhang

Journal of Marine Science and Technology–Taiwan

Nonlinear characteristics are very common in marine steam turbine, such as control input constraints and external disturbances. Based on the active disturbance rejection control (ADRC), an anti-windup scheme is proposed to eliminate the undesired effects of nonlinear characteristics in the control system. In this scheme, firstly, a method of setting parameter is designed for nonlinear active disturbance rejection control (NLADRC). Then, two kinds of anti-windup schemes are proposed in this paper for NLADRC in the presence of control input constraints and external disturbances. Finally, simulation study is carried out for a first order delay object with actuator constraints, simulation results …

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A Fast Automated Vision System For Container Corner Casting Recognition, Chao Mi, Zhiwei Zhang, Youfang Huang, Yang Shen Feb 2016

A Fast Automated Vision System For Container Corner Casting Recognition, Chao Mi, Zhiwei Zhang, Youfang Huang, Yang Shen

Journal of Marine Science and Technology–Taiwan

With the development of container port automation, the automated vision systems for containers have been widely used in automated ports. This paper presents a rapid automated vision system for container corner casting recognition. The histograms of oriented gradients (HOG) descriptors are used to preprocess the image of the container and the vectors of HOG are then built. A trained support vector machine (SVM) classifier is applied to recognize the right corner casting of the container. At last, through symmetry, a flipping mirror algorithm is used for quick left corner casting recognition. The experimental results show this algorithm scans and detect …

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A Novel Strategy For Stowage Planning Of 40 Feet Containers In Container Terminals, Ning Zhao, Yifan Shen, Mengjue Xia, Jian Jin Feb 2016

A Novel Strategy For Stowage Planning Of 40 Feet Containers In Container Terminals, Ning Zhao, Yifan Shen, Mengjue Xia, Jian Jin

Journal of Marine Science and Technology–Taiwan

Owing that the container terminals increasingly secure a crucial position in today’s container transportation, the stowage planning, which is one of the important process during container-loading operations, gradually attracts the attention of terminal operators. In this paper, we discuss the vessel stowage planning problem for 40 feet outbound containers, in which a strategy named ‘ROIR’ is analyzed. By carefully studying the operational flow of vessel stowage, a multiobjective mixed integer programming model is put forward with regard to general principles. Then a specified genetic algorithm is proposed to solve the IP model. An integer encoding technique is employed in the …

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Theoretical Analysis And Sph Simulation For The Wave Energy Captured By A Bottom-Hinged Owsc, Yu-Chi Chang, Da-Wei Chen, Yi-Chih Chow, Shiaw-Yih Tzang, Chen-Chou Lin, Jiahn-Horng Chen Dec 2015

Theoretical Analysis And Sph Simulation For The Wave Energy Captured By A Bottom-Hinged Owsc, Yu-Chi Chang, Da-Wei Chen, Yi-Chih Chow, Shiaw-Yih Tzang, Chen-Chou Lin, Jiahn-Horng Chen

Journal of Marine Science and Technology–Taiwan

This paper examines one type of wave energy converter, the Oscillating Wave Surge Converter (OWSC) with its bottom hinged on the sea bed. The simplest form of OWSC is a flapper connected with a power take-off (PTO). Theoretical analysis based on a 2D linear potential theory elucidates the mechanisms of the wave energy capture by a bottom-hinged OWSC in terms of impedances associated with the wave field, the flapper body, and the PTO. Criteria of impedance canceling and matching to maximize the energy capture factor can be deduced. Smoothed Particle Hydrodynamics (SPH) is established for simulating the same problem, and …

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Improved Boundary Values Of Ocean Wave Fields Using A Data Assimilation Scheme, Yang-Ming Fan, Heinz Günther, Dong-Jiing Doong, Chia Chuen Kao Dec 2015

Improved Boundary Values Of Ocean Wave Fields Using A Data Assimilation Scheme, Yang-Ming Fan, Heinz Günther, Dong-Jiing Doong, Chia Chuen Kao

Journal of Marine Science and Technology–Taiwan

The objective of this study was to assess the accuracy of numerical wave forecasts through data assimilation of boundary values. A sequential data assimilation scheme was adopted to utilise altimeter data. The performance of the system in terms of operational applications, specifically for typhoon waves, was investigated. Two typhoons that occurred in 2006 around Taiwan (Kaemi and Shanshan) were used as case studies. The proposed data assimilation increased the forecast accuracy of the boundary values in terms of the wave parameters, such as the wave heights and periods. The results showed that after the assimilation, the assimilation model was significantly …

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Evaluation Of Tidal Stream Energy Around Radial Sand Ridge System In The Southern Yellow Sea, Jinhai Zheng, Jisheng Zhang, Jun Wang, Aifeng Tao Dec 2015

Evaluation Of Tidal Stream Energy Around Radial Sand Ridge System In The Southern Yellow Sea, Jinhai Zheng, Jisheng Zhang, Jun Wang, Aifeng Tao

Journal of Marine Science and Technology–Taiwan

Tidal stream energy as a new type of marine renewable energy attracts more and more attention of coastal engineers due to its advantages of great power density, long-term predictability and low environment impact. The radial sand ridge (RSR) system is located in the southern Yellow Sea off the Jiangsu coast, China, and it is characterized by a radial current field. The exploitation of tidal stream energy in the RSR system means great significance to the local industry and ecosystem of this region. In this study, a two-dimensional depthaveraged hydrodynamic model was established to predict one-year tidal hydrodynamics in the RSR …

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The Latest Progress In Wave Energy Conversions In China And The Analysis Of A Heaving Buoy Considering Pto Damping, Hong-Da Shi, Fei-Fei Cao, Na Qu Dec 2015

The Latest Progress In Wave Energy Conversions In China And The Analysis Of A Heaving Buoy Considering Pto Damping, Hong-Da Shi, Fei-Fei Cao, Na Qu

Journal of Marine Science and Technology–Taiwan

Wave energy conversions are being widely researched and developed in China; two key factors of significance with these devices are safety and efficiency. This paper provides information on the latest techniques of wave energy devices investigated in China, introduces their working principles, and describes performance briefly. To design a wave device, the conversion efficiency needs to be estimated. This paper describes a method for doing such analysis on a heaving buoy considering the power take-off, which is an important step for achieving wave-to-wire simulation.

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Current-Induced Seabed Scour Around A Pile-Supported Horizontal-Axis Tidal Stream Turbine, Jisheng Zhang, Peng Gao, Jinhai Zheng, Xiuguang Wu, Yuxuan Peng, Tiantian Zhang Dec 2015

Current-Induced Seabed Scour Around A Pile-Supported Horizontal-Axis Tidal Stream Turbine, Jisheng Zhang, Peng Gao, Jinhai Zheng, Xiuguang Wu, Yuxuan Peng, Tiantian Zhang

Journal of Marine Science and Technology–Taiwan

Tidal stream energy has attracted more and more attentions of researchers and engineers of coastal studies in recent years, as it is renewable, predictable and environmentally friendly. Although many efforts have been made for the application of tidal stream energy, the scouring process in the vicinity of a pile-supported tidal stream turbine remains unclear. This study develops a mathematical model, consisting of hydrodynamic module, General Moving Object (GMO) module and sediment scour module, to numerically investigate the fluidstructure interaction and its induced sediment scour process around such a combined structure. Only a steady current is considered in the model, and …

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Yet Another 100yr Storm Surge Event: The Role Of Individual Storm Surges On Design Water Levels, Jürgen Jensen, Arne Arns, Thomas Wahl Dec 2015

Yet Another 100yr Storm Surge Event: The Role Of Individual Storm Surges On Design Water Levels, Jürgen Jensen, Arne Arns, Thomas Wahl

Journal of Marine Science and Technology–Taiwan

On December 6th 2013 the German coastline was hit by the extra tropical cyclone “Xaver”, which caused the highest water levels on record in some places. In the media, the resulting storm surge was quickly referred to as a “once in one hundred years” event or a “century storm surge”. Based on 12 tide gauges in the German Bight, we estimate return periods of the observed water levels during Xaver and find that they were much lower than 100 years. However, in some places Xaver caused increases in the 200-year return water level estimates, which are often used for the …

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Characteristics Of Boundary Layer Flow Induced By Solitary Wave Propagating Over Horizontal Bottom, Chang Lin, Shi-Min Yu, Po-Hung Yeh, Min-Hsuan Yu, Ching-Piao Tsai, Shih-Chun Hsieh, Ming-Jer Kao, Guang-Wei Tzeng, Rajkumar Raikar Dec 2015

Characteristics Of Boundary Layer Flow Induced By Solitary Wave Propagating Over Horizontal Bottom, Chang Lin, Shi-Min Yu, Po-Hung Yeh, Min-Hsuan Yu, Ching-Piao Tsai, Shih-Chun Hsieh, Ming-Jer Kao, Guang-Wei Tzeng, Rajkumar Raikar

Journal of Marine Science and Technology–Taiwan

Experimental results on the flow characteristics of bottom boundary layer induced by a solitary wave propagating over a horizontal bottom are presented. Particle-trajectory flow visualization technique and high-speed particle image velocimetry (HSPIV) were used to elucidate detailed velocity fields underneath solitary waves with the ratios of wave height to water depth from 0.130 to 0.386. The results show that the velocity profiles can be classified into two classes with respect to the passage of the solitary wave-crest at the measuring section: the pre-passing and post-passing phases. For the pre-passing phase, the velocity distributions can be deduced to a unique similarity …

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Experimental Study On The Erosion Stability Of Coarse Grain Materials Under Waves, Alexander Schendel, Nils Goseberg, Torsten Schlurmann Dec 2015

Experimental Study On The Erosion Stability Of Coarse Grain Materials Under Waves, Alexander Schendel, Nils Goseberg, Torsten Schlurmann

Journal of Marine Science and Technology–Taiwan

Large-scale hydraulic model tests were carried out by the Leibniz University of Hannover, Germany to investigate the performance of wide-graded grain materials (0.1-200 mm) as scour protection system tested under spectral wave loads. The model tests were conducted in the Large Wave Flume (GWK) of the Forschungszentrum Küste (FZK) assuming a length scale of 1:4. The experimental setup consisted of a single layer material bed protecting a monopile (D = 1 m) as often used as offshore supporting structure. In order to measure the structure-induced scour development around the monopile acoustic backscatter systems (ABS), single-beam echosounder, and a 3D laser …

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Assessment Of Changes Of Extreme Wave Conditions At The German Baltic Sea Coast On The Basis Of Future Climate Change Scenarios, Norman Dreier, Christian Schlamkow, Peter Fröhle, Dörte Salecker, Zhenshan Xu Dec 2015

Assessment Of Changes Of Extreme Wave Conditions At The German Baltic Sea Coast On The Basis Of Future Climate Change Scenarios, Norman Dreier, Christian Schlamkow, Peter Fröhle, Dörte Salecker, Zhenshan Xu

Journal of Marine Science and Technology–Taiwan

Information on possible changes in extreme wave heights is needed to determine the future effectiveness and safety of coastal and flood protection structures. In this study, an assessment of possible changes in the extreme wave heights at selected locations along the German Baltic Sea coast has been carried out on the basis of numerical simulations of waves in the western Baltic Sea and regional climate model data for the past and the future (1961-2100). The future climate change signal of significant wave heights with a return period of 200 years mainly depends on: (i) the location, (ii) the climate change …

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Seabed Scour Around A Breakwater A Case Study In Mailiao Harbor, I-Fu Lin, I-Fan Tseng, Chung-Pan Lee, Guan-Yu Chen Dec 2015

Seabed Scour Around A Breakwater A Case Study In Mailiao Harbor, I-Fu Lin, I-Fan Tseng, Chung-Pan Lee, Guan-Yu Chen

Journal of Marine Science and Technology–Taiwan

According to a field measurement in 2012, the bathymetry in the area of Mailiao Harbor, located in the middle of Taiwan's west coast, has scouring hole with a size distribution of approximately 500 x 100 m. The maximum scour depth is 26 m (from -22 m eroded to -48 m). Although scour has become a major threat to breakwaters and navigational safety, it can be predicted cost-effectively, reliably, and rapidly by applying the computational fluid dynamics (CFD) numerical simulation. In this study, numerical simulation of tidal current and typhoon waves was performed to investigate the causes of the scouring hole …

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