Zhu, Zhixia (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University Shanghai, China) | Yang, Yang (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University Shanghai, China) | Zhou, Ke (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University Shanghai, China)
The Typhoon 9711（Winnie）affected the East China Sea in 1997. In this paper, the radius of maximum winds is calculated by method of experiential formula（MEF）or method of gale cycle retrieval (MGCR)，and the parameter typhoon wind model(PTWM), which is derived from Jelesnianski2 wind formula and Fujita pressure formula(FPF), FPF and the third-generation deep-sea wave model(WAVEWATCH-Ⅲ) are applied to hindcast the storm waves induced by the typhoon Winnie. The comparisons and analyses between the simulation results and observation data indicate that: during the typhoon Winnie, the distribution of modeled storm-waves in Northwest Pacific Ocean, which is simulated by MEF, is more reasonable. Comparing the significant wave height calculated and measurements in three offshore stations, the error is about 10%, and it shows that MEF is better than MGCR.
China with long coastline lies in the west bank of Pacific Ocean which is the most active area of tropical cyclones of the world, therefore the disaster which caused by typhoon is very serious in China. Research has shown that the destructivity of the huge waves caused by typhoon is far greater than that of typhoon itself, and every year the direct economic losses amounted to hundreds of millions of dollars. For example, in China neritic province there were 35 times wave processes in 2004, whose significant wave height were above 4 meters, causing direct economic losses amounting to 207,000,000 Yuan. The U.S. National Oceanic and Atmospheric Administration (NOAA) had established several ocean waves service forecast systems by using WAVEWATCH-Ⅲ and had achieved good results already. The ocean waves service forecast systems include the global forecast system having a resolution ratio of 1.25 longitude×1 latitude, and regional forecast system having a resolution ratio of 0.25 longitude×0.25 latitude and covering Alaska sea area, the Northwest Atlantic, Northeast Pacific and North Atlantic（Wen B and Yu F ,2008）.
Broglia, R. (INSEAN - Italian Ship Model Basin Rome, Italy) | Bouscasse, B. (INSEAN - Italian Ship Model Basin Rome, Italy) | Di Mascio, A. (INSEAN - Italian Ship Model Basin Rome, Italy) | Lugni, C. (INSEAN - Italian Ship Model Basin Rome, Italy) | Atsavapranee, P. (NSWCCD - aval Surface Warfare Center Cardrock Division West Bethesda, MD, USA)
An experimental and numerical study of the free roll decay motion for a vessel of the Italian Navy is presented. Experimentally both sea trials and model scale tests have been carried out; numerical analysis has been performed by means of unsteady RANS simulations. The focus is on the analysis of the roll motion coefficients (damping and period of oscillations) at different Froude and Reynolds numbers. To this aim, experiments and numerical simulations were carried out at different Froude and Reynolds numbers. Sea trials were carried out on the Italian Navy ship Comandante Bettica in the Mediterranean Sea, close to the coast of Sicily; models experiments were performed in the towing tank at INSEAN. Computations were carried out by means of an inhouse unsteady RANS solver.
The analysis of the roll motion of a ship is of practical interest for both safety and comfort reasons. In this paper an experimental and numerical analysis of the roll decay for patrol boat of the Italian Navy is carried out. Full scale trials in the Mediterranean sea in cooperation with NSWCCD (Naval Surface Warfare Center, Carderock Division) and model scale experiments at the INSEAN towing tank have been performed. For a proper comparison, hull in fully appended configuration, (i.e. with the rudders, bilge keels, fins, and propeller apparatus, including struts, A-brackets and the propeller shaft) has been considered. To properly understand the effect of the rotating propeller on the roll damping, model scale experiments have been performed with and without the rotating propeller. Several Froude numbers have been considered, both in full and model scale, to highlight the effect of the ship speed on the roll damping. Numerical simulations have been carried out for three different Froude numbers; the steady flow around the vessel with a fixed heel angle, and the unsteady free roll decay of the vessel from an initial of heel angle of 10 degrees are computed.
A hydraulic test frame has been designed to apply the simultaneous actions of tension, twist and partial sheave bending loads on cable specimens. This paper reports on its use in evaluating a finite element program for modeling the structural behavior of cables and wire rope. Computer model and test results are compared and found to be in good agreement.
This paper describes the design of a novel cable test frame and its use in providing test data needed to evaluate the cable finite element analysis computer code, CableCAD® (2009). Approximately 200 cable tests in tension, twist and bending were performed. A sample of these tests; viz., tension-twist of an electrical-mechanical cable and tensionbending of a 1x19 wire strand, are presented here. Cable specimens were tension-twist tested and a wire rope was subjected to bend-oversheave tests to determine the bend diameter that causes wire slip. Cable specimens were dissected to obtain accurate geometrical properties including component diameters, layer diameters, and lay lengths and directions. Material properties were obtained from manufacturers. Specimens were terminated with fittings following recommended industry practice. All specimens tested were preconditioned with a minimum of 15 tension cycles to eliminate “constructional stretch.” Peak cyclical tension values were equal to the final test values. Test measurements include real-time data acquisition of reaction torque, cable elongation and diameter change in response to applied tension, twist and bending loads. With known geometrical and material details, computer models were created and analyzed. Model and test results are compared.
CABLE TEST FRAME
A new test frame design capable of horizontally testing specimens up to 5.6 m in length is described in Figs. 1 and 2(Refer to the full paper). The test frame applies up to a 445 kN tension at one end of the test frame and a maximum 1,130 N-m torque can be input at the opposite end of the test frame.
Bellendir, E.N. (The B.E. Vedeneev VNIIG, Inc. St.-Petersburg, Russia) | Finagenov, O.M. (The B.E. Vedeneev VNIIG, Inc. St.-Petersburg, Russia) | Nikitina, N.Ya. (The B.E. Vedeneev VNIIG, Inc. St.-Petersburg, Russia)
The risk analysis and assessment for mooring hydraulic facilities of offshore oil and gas production objects have been made in order to validate the normal level of safety of the facilities at the operation stage. Very intense loads of various types acting on the facilities are taken into account; seismic, ice, wave and thermal ones typical for the offshore zone of Sakhalin Island are the main of them. In addition, the risk of lean-on of vessels of different dead weight (including significant one) on the facilities has been analyzed in detail. The results of the risk analysis allow validation of the scenarios of the most probable and the most severe failures at the mooring hydraulic facilities and quantitative estimation of the average annual probability (frequency) and damage from the failures. The obtained values confirm that the risk of failure of the mooring hydraulic facilities at the operation stage is acceptable (tolerable).
The Liquefied Natural Gas (LNG) plant which is a part of the complex of oil and gas production complex at Sakhalin shelf consists of two processing liquefying lines, gas storages (LNG terminal) and LNG loading objects.
The territory of LNG plant consists of five areas for managing main and auxiliary processes and accommodating services:
• main processing area in the center of the territory which consists of two processing lines for gas liquefying, a power station and general engineering facilities;
• LNG terminal at the south-west of the liquefying lines;
• trestle and LNG loading berth in the water 850 m to the south of the two LNG storage tanks, with two loading lines;
• area of administrative and repair services to the north of the general facilities and power units;
• flare facilities to the north of gas liquefying lines.
Binugroho, Eko Henfri (School of Mechanical Engineering, Pusan National University Busan, South Korea) | Ha, Tae Kyu (School of Mechanical Engineering, Pusan National University Busan, South Korea) | Choi, Jae Weon (School of Mechanical Engineering, Pusan National University Busan, South Korea) | Ko, Nam Gweon (School of Mechanical Engineering, Pusan National University Busan, South Korea) | Seo, Young Bong (Innovation Center for Engineering Education, Pusan National University Busan, South Korea)
This paper discusses the design of an open control platform (OCP) and modeling of hovering type AUV testbed. A publisher/subscriber architecture that use ACE/TAO Real-time Event Service (RTES) as the middleware core is chosen to develop the OCP structure. The designed OCP uses an event-based communication that addresses the real-time transfer of control and data among AUV components which coordinate with each other in a loosely coupled fashion. To perform the real-time performance, several services in RTES are collaborated in the system such as event filtering, correlation, scheduling, and priority setting to meet the quality of service (QoS) requirement of each AUV component. Performance of the software platform is examined with an experiment that simulates data transfer of AUV sensor’s data. On the other hand, AUV testbed that designed using hovering type with two hulls and four thrusters has been modeled. PD controller has been applied as the AUV controller for surge (x-axis positioning), heave (depth) and yaw (steering). Together with the thruster’s model and controller, the AUV model and its controller have been simulated under OCP environment.
During the last decade, the area of information technology has sustained a remarkable level of growth. Processor speed, memory capacity, network bandwidth, and other metrics of progress in computing technology grow in their exponential trends. The advance in the fabrication technology makes computing devices not only have an improvement in performance but also give more benefits such as; smaller in size, lower in price and lower power consumption. In another part, control theory and engineering have a remarkably successful history of enabling automation, and information-centric control. Complex control systems for autonomous vehicles require integrating new control algorithms with a variety of different component technologies and resources. These components are often supported on different types of hardware platforms and operating systems and often must interact in a distributed environment. Due the lacks of standard it is almost impossible to easily use those design into new application.
Lin, Ting-Chieh (Research Center of Ocean Environment and Technology, National Cheng Kung University Tainan, TAIWAN, China) | Hsiao, Shih-Chun (Department of Hydraulic and Ocean Engineering, National Cheng Kung University Tainan, TAIWAN, China) | Hwang, Kao-Shu (Tainan Hydraulics Laboratory, National Cheng Kung University ainan, TAIWAN, China)
This paper describes impulsive wave force due to breaking solitary waves impinging and overtopping an impermeable breakwater upon a sloping beach. A two-dimensional volume of fluid (VOF) type numerical model named COBRAS (COrnell BReaking And Structure), based on the Reynolds-Averaged Navier-Stokes (RANS) equations and the k - ε turbulence closure model, is firstly calibrated against present laboratory experiments with fairly good agreements and then employed to study the impulsive wave force correlated with structure failure mechanisms due to waves interacting against the breakwater. Both the effects of wave nonlinearity and freeboard are addressed. Influence of entrapped air-bubble accompanied breaking waves on reducing wave force is also discussed.
Historical tsunami survey literature points out that the devastating tsunami power is relevant to wave run-up inundation combined with floating debris on shorelines, in which significant wave force of impulsive tsunami wave could destroy inland community and alongshore infrastructure (e.g. Yamamoto et al., 2006). Various impulsive waves would occasionally give rise to different structure failure mechanisms (Kato et al., 2005), and also allow particular wave dynamics to affect alongshore flow fields on structure damage (Tokin et al., 2003). The knowledge of wave-structure interaction is therefore of crucial importance for tsunami hazard mitigation. Over the past decades it can be seen that the subject of wave-structure interaction under solitary-like long waves have been received marvelous attention on tsunami wave research (Synolakis and Bernard, 2006), such as run-up/run-down on a sloping beach (e.g. Lin et al., 1999; Hsiao et al., 2008), disintegration and transmission properties of waves over an abrupt topography (e.g. Losada et al., 1989; Liu and Cheng, 2001), and dynamic vortex shedding and advection around a submerged obstacle or a sub-aerial plate (e.g. Chang et al., 2001). However, the information combined solitary wave impingement with overtopping flow upon a coastal structure is relatively rare.
Rafiee, Ashkan (School of Mechanical Engineering, The University of Western Australia Crawley, WA, Australia) | Thioagarajan, Krish P. (School of Mechanical Engineering, The University of Western Australia Crawley, WA, Australia) | Monaghan, Joseph J. (School of Mathematical Science, Monash University Clayton, VIC, Australia)
In this paper the Smoothed Particle Hydrodynamics (SPH) method is applied to the violent sloshing flows in a 2D rectangular tank under a harmonic sway excitation motion. A fully explicit predictor-corrector time stepping scheme is proposed which uses the pressure Poisson equation in the corrector step to satisfy the incompressibility constraint. A method is introduced for identifying free surface particles and imposing the Dirichlet boundary condition on them. The no-slip boundary condition on solid boundaries is satisfied automatically by the proposed approach for dealing with boundary particles. Numerical simulations have been performed for the Daewoo Shipbuilding and Marine Engineering (DSME) rectangular tank model, case indexes: LR2F1A1, L-R2F1A2.
Free surface sloshing in a moving container constitutes a problem of great practical importance with regard to the safety of transportation systems, such as tank trucks on highways, liquid tank cars on railroads and sloshing of liquid cargo in ocean-going vessels. Sloshing is an important issue for Liquefied Natural Gas (LNG) tanks and in general when partially filled tanks are on-board of a vessel. This resonance phenomenon may be connected with complex motions of the filled liquid that can couple with ship motions and can represent a danger for the tank structure and for the stability of the ship. On the other hand when the frequency of the tank motion is close to the natural frequency of the interaction between the structure and the sloshing fluid, the fluid motion exerts high impact load on the tank wall. At certain filling ratio it may also create high impact loads on the ceiling of the tank causing structural damage. Therefore identifying the behavior of the fluid flow during sloshing is crucial in the design of the tanks (Akyildiz et al., 2005; Kim et al., 2005).
Moirod, Nicolas (Bureau Veritas, Marine Division, Research Department Neuilly-Sur-Seine Cdx) | Baudin, Eric (Bureau Veritas, Marine Division, Research Department Neuilly-Sur-Seine Cdx) | Henry, Jacqueline (Bureau Veritas, Marine Division, Research Department Neuilly-Sur-Seine Cdx) | Diebold, Louis (Bureau Veritas, Marine Division, Research Department Neuilly-Sur-Seine Cdx) | Zalar, Mirela (Bureau Veritas, Marine Division, Research Department Neuilly-Sur-Seine Cdx)
This paper presents various aspects of seakeeping/sloshing coupling, addressing among the other BV developments of efficient numerical tool to predict this dynamic coupling, influence of this coupling for various LNG projects in terms of motion response and in terms of induced sloshing effects through dedicated sloshing model test campaigns.
The proposed paper deals with Bureau Veritas methodology and procedures for the analysis of hydrodynamic and sloshing responses of LNG vessels operating as LNG terminals in wide range of operational conditions. The particular application covers external wave loading and internal sloshing loading in LNG cargo tanks, including the dynamic effects of their mutual hydrodynamic interaction. Sloshing feasibility analysis is the core of Bureau Veritas sloshing assessment. State of the art of sloshing analysis relies on small-scale sloshing model tests supported by extensive developments of CFD computation techniques, commonly studying one isolated tank submitted to the forced motion without their mutual interaction. In reality, wave-induced response of the vessel carrying liquid cargo is affected by internal liquid motion, and consequently, tank liquid flow is altered by the vessel motion in return. This paper presents various aspects of such seakeeping/sloshing coupling, addressing among the other BV developments of efficient numerical tool to predict this dynamic coupling, the influence on transverse first order motions identified by experimental campaigns, validation of these numerical models through experiments such as measurement of the global forces exerted by the moving fluid in the tank and dedicated wave basin tests where the hull and the tanks are modeled. The influence of hydrodynamic coupling is illustrated through the application for various LNG terminal projects; from currently operating LNG RVs (Liquified Natural Gaz Regasification Vessel) over the potential conversion of existing ships in service to the new buildings of LNG FPSOs (Floating Production Storage and Offloading) or LNG FSRUs (Floating Storage and Regasification Unit) and for different tanks’ arrangements.
Liu, Ta-Kang (Institute of Ocean Technology and Marine Affairs, National Cheng-Kung University, Research Center of Ocean Environment and Technology, National Cheng Kung University Tainan, TAIWAN, China) | Yu, Jin-Li (Institute of Ocean Technology and Marine Affairs, National Cheng-Kung University) | Wei, Ping-Sheng (Institute of Ocean Technology and Marine Affairs, National Cheng-Kung University) | Hwung, Hwung-Hweng (Research Center of Ocean Environment and Technology, National Cheng Kung University Tainan, TAIWAN, China)
The nearshore water body, particularly in estuarine area, is an important interface for transporting land-based contaminants into the coastal ocean. This estuarine area is a very productive ecosystem due to its abundant organic matters, nutrients, and diverse biota. Estuarine water quality can be significantly affected by the tidal cycles due to the discharge of land-based pollutants from waterways to coastal area during ebb tides. A semi-continuous water quality monitoring system was installed in Yunlin Offshore Industrial Park (YOIP), the largest industrial park in Taiwan, since 2006 to provide real-time water quality information such as pH, ORP, water depth, dissolved oxygen, temperature, turbidity, conductivity, and chlorophyll. To interpret the large quantities of high-frequency data generated by this system, information theory was applied for data processing and extraction of useful information for further coastal water quality management. Shannon entropy and Fisher information were calculated in this study to explore their applicability for signaling possible coastal pollution events in the YOIP. Results showed that Shannon entropy is a better indication than the raw monitoring data, especially for turbidity and salinity. When Shannon entropy was higher, multiple instable turbidity readings were observed. We conclude that these information contents may be a useful new tool for exploratory data analysis to signify some episodes of water quality degradation.
There are several advantages for industrial development in coastal area such as easy access to port, lower land cost, convenient transport of raw materials, and the availability of large amount of cooling water. In response to the rapid development of industry and growing land demands during the 1980s, Taiwan’s Industry development Bureau (IDB) has constructed Yunlin Offshore Industrial Park (YOIP). This largest industrial park in Taiwan highlights the country’s aggressive expansion of her coastal territory and land reclamation policy. Although reclamation projects provide valuable land, they also create various engineering, environmental, socioeconomic, and ecological problems in coastal areas.
Zhao, Xiaodong (School of Electromechanical Engineering, Zhejiang Ocean University Zhoushan, Zhejiang, China) | Yang, Jie (School of Electromechanical Engineering, Zhejiang Ocean University Zhoushan, Zhejiang, China) | Fan, Xiqiu (School of Electromechanical Engineering, Zhejiang Ocean University Zhoushan, Zhejiang, China) | Duan, Jizhou (Institute of Oceanology, Chinese Academy of Sciences Qingdao, Shandong, China)
In the presence of sulfate-reducing bacteria(SRB), hematite(α-Fe2O3) dissolution is affected potentially by a combination of enzymatic (hydrogenase) reduction with hydrogen sulfide oxidation. As a consequence, ferrous ions are free to react with excess H2S to form insoluble iron sulfides. Morphology of single crystalline hematite cubes, prepared by a hydrothermal synthesis at 130°C from a solution of urotropine ((CH2)N4) and ferric chloride, and its metamorphosis to iron sulfides in SRB-containing medium are observed by transmission electron microscopy in the present study. Iron oxide hydrate (Fe2O3·H2O) and the γ-FeOOH form of hydrated ferric oxide are the primary forms of corrosion product. Two typical morphologies of iron sulfides, globule and plate, are observed after immersion of about a month. The morphological changes of the corrosion product are interpreted from analyses made using energy dispersive spectroscopy (EDS) and the spectra confirm that the plates and the globules are different morphologies of the same chemical species, iron sulphide product. Electron diffraction identifies the presence of a hexagonal structure associated with observed crystallites, indicating the identification of the iron sulfide phase as pyrrhotite.
Sulfate-reducing bacteria, belonging to anaerobe, exist widely in the polluted seawater and sea mud. SO42- can be reduced to S2- by their metabolic activities, and H2S formed in aqueous solution results in the corrosion damage of metal pipelines and constructions, as well as pollution of environment. Comprehensive research has been carried out in terms of microbiologically influenced corrosion (MIC) of carbon steel and low alloy steel in environment containing SRB(Tiller,1983). Iron oxide occurs with the formation of ferrous sulfide or before it in the primary stage of the corrosion process. Iron oxide should be responsible for the emergence and development of MIC, which haven’t been well investigated yet. In the environment abundant in sulfide, metal oxide may react with sulfide as the resource of metal ions.