-
Study on synthesis optimisation of speed and sea keeping performance based on on-line simulation of high-speed single-hull ship
AuthorsYi Wang ; Sing-lin Yang
Date published2006
AbstractThe main elements of the navigation performance of a ship are its speed its manoeuvrability and its seakeeping. The mathematical model of a high-speed single hull ship's propulsion system (adjustable-pitch screw propulsion) is firstly established. Then based on MATLAB the simulation model of the propulsion system is built with the help of simulation software 'Simulink'. The intelligent control on the propulsion system is carried out using fuzzy controller of Look-Up Table. After that the mathematical model of synthesis optimisation of high-speed single-hull ship is established by considering control speed and seakeeping performances. Based on the aforementioned established simulation model and applying GAOT MATLAB's optimisation toolbox for GA (Genetic algorithm) the optimisation design of the system is carried out. An example is given and the accuracy and reliability of the simulation and optimisation models are validated.
AuthorsYi Wang ; Sing-lin Yang
Date published2006
-
Effects of avoidance of heavy weather on the wave induced load on ships
AuthorsZhi Shu ; Torgeir Moan
Date published2005
AbstractWave-induced hull girder loads such as vertical bending moment amidships are very important for design. The effect of heavy weather avoidance on the long-term wave-induced loads on ships is evaluated. Two hydrodynamic codes VERES based on a 2D strip theory and WASIM based on a 3D Rankine panel method are used to calculate the wave-induced loads and motions on various vessels. Two models for heavy weather avoidance are proposed. The first is based on the assumption that operational criteria relevant to vertical acceleration green water and bottom slamming are fulfilled. The second is based on the assumption that the sea state forecasts are available to the shipmaster and that rerouting is made. Based on the first model considering avoidance of heavy weather and the hydrodynamics results calculated from two codes wave-induced hull girder loads are obtained. The results are discussed - in particular the effect of different hydrodynamic codes and various scatter diagrams. The long-term prediction of wave-induced hull girder loads considering the effect of avoidance of heavy weather will give a relatively more realistic evaluation of the extreme hull girder loads. Finally the results from ship rules are also re-evaluated compared with the long-term prediction with and without heavy weather avoidance.
AuthorsZhi Shu ; Torgeir Moan
Date published2005
-
Report on the investigation of a fatal accident on baord Arco Adur on the River Medway 25 February 2003
AuthorsMarine Accident Investigation Branch
Shelf Location40e
AuthorsCatalogue numberMarine Accident Investigation Branch
UNK
Shelf Location40e
-
On the sidewall effects on the non-linear wave loads on a TLP-like structure in a wave tank: analysis of the non-linear near-trapping
AuthorsFabrizio d'Este ; Riccardo Codiglia ; Giorgio Contento
Date published2002
AbstractThe non-linear interaction in diffraction regime of regular waves with a TLP-like structure is studied using the Numerical Wave Tank method. In particular the higher order 'near trapping' phenomenon is analysed with emphasis on the sidewall reflection effects on the harmonic components of the wave elevation and of the forces on the cylinders. From prelimineary results using the Fourier analysis with the sliding window technique it seems that first order in-line terms is only weakly affected by the dimensions of the basin whereas the first order side force on the lateral cylinder shows evident interference effects. At the same time the amplitude of the second order terms of the forces shows a smoother variation with time for the larger basin.
AuthorsFabrizio d'Este ; Riccardo Codiglia ; Giorgio Contento
Date published2002
-
Reports on Researches carried out in the William Froude National Tank, between the years 1908-1921
AuthorsNational Physical Laboratory
Shelf Location235g
AbstractContents include: Report of the Experimental Tank Committee (1908), Report on the progress of the National Experimental Tank, The William Froude National Tank and its equipment. Also, the following articles: The effect of bilge keels on the rolling of lightships; Methodical experiments with mercantile ship forms; Effect of form and size on resistance of ships; Skin friction; Effect of longitudinal motion of a ship on its statical transverse stability; Speed, dimensions and form of cargo vessels; Model experiments on the effect of beam on resistance of mercantile ship forms; Model experiments in connection with submarine warfare. Includes numerous charts and diagrams.
AuthorsPublisherNational Physical Laboratory
London ; His Majesty's Stationery Office (HMSO)
Catalogue number623.8
Shelf LocationDate published235g
1924
-
A study on the decrement of work efficient by the oscillation
AuthorsYoshiaki Kawamura ; Kuniyaki Shoji ; Kiyokazu Minami et al.
Date published2002
AbstractIt is expected that construction work on a very large floating structure similar to the MEGA-FLOAT will increase. The working characteristic and the effect on board of oscillating ships by measuring the finger pulse is investigated. The effect of oscillating working conditions on the human body is investigated. Experiments are carried out to analyse the trend of decreasing work efficiency and the effect on workers' motion using various methods. The first experiment investigates the effect of oscillation upon physical motion. This experiment considers walking motion on the passage. The next experiment examined considers the effect on sensitive work. In this experiment the amount of the water poured into the empty bottle from the kettle is observed. The third experiment evaluates the relation between oscillation and thinking capability resulting from a simple test of calculation. Results of this study have shown that the decrease in work efficiency is closely connected to the delayed reaction of the human body with the oscillation.
AuthorsYoshiaki Kawamura ; Kuniyaki Shoji ; Kiyokazu Minami et al.
Date published2002
-
Biofuels and their effect on the shipping industry
AuthorsR Sadler
PublisherIMarEST
AbstractBiofuels are already influencing the shipping trade but are designers and ship owners thinking far enough ahead to accommodate their influence on the world fleet of the future? The impact of biofuel industrial growth with relation to shipping is not well analysed and there is much contradictory information making the future very difficult to predict. This lecture performs a multidisciplinary analysis of biofuels covering their background the economic political and social drivers for their use and the consequential impact on ship design and operation with the intention of promoting further debate on both the effects of biofuels as a fuel and a cargo for ships. Biofuels are described under the commonly referred to three generations. And comparison with the automobile and aviation industries use of biofuels is drawn Analysis of the demand of both the European and Asian sectors is covered. The impact of these new technologies on shipping routes and port facilities is also discussed. This analysis finds that current political legislation on biofuel use is dependent on technology not economically available.
AuthorsDate publishedR Sadler
2008
PublisherIMarEST
-
Experimental investigation of vortex-induced vibration on an inclined circular cylinder
AuthorsAndre L C Fujarra ; Ricardo Franciss ; Julio R Meneghini et al.
Date published2007
AbstractThis paper presents experimental results of vortex-induced oscillations of an inclined circular cylinder mounted on an elastic base. Models are mounted on an air-bearing elastic base instrumented with strain gages accelerometers and a load cell. The experiments were carried out on a water channel facility at NDF-EPUSP. New measurements on the dynamic response oscillations of this inclined cylinder due to vortex-induced vibrations (VIV) are compared with previous experiments on a vertical cylinder. VIV is investigated by conducting experiments in two ways. First the cylinder is maintained vertical on the elastic base with a uniform current normal to its axis and the response curve is obtained. Subsequently the investigation is carried out changing the angle of inclination from 0 to 45 degrees in relation to vertical.
AuthorsAndre L C Fujarra ; Ricardo Franciss ; Julio R Meneghini et al.
Date published2007
-
Field test results of a rotary separator turbine on the Ram- Powell TLP
AuthorsC H Rawlins ; G D Ross
Date published2001
AbstractThe RST (rotary separator turbine) and skid package is used in the first offshore field trial of this technology on the Ram-Powell TLP (tension leg platform) located in the Gulf of Mexico. The RST is a compact gas-liquid separation and power generation device designed to operate on process fluid pressure. It offers a potential 50% weight and space savings over conventional vessel separators and is under development for use on minimum footprint facilities. The purpose of the trial is to verify the separation and mechanical characteristics in actual production conditions. An integrated test package installed on the Ram-Powell TLP in June 2000 tested the RST on actual well production. Photographs and diagrams appear on pages 5 to 6.
AuthorsC H Rawlins ; G D Ross
Date published2001
-
Inversion of broadband acoustic data on a single hydrophone by use of an equivalent geoacoustic model
AuthorsJ C Le Gac ; M Asch ; Y Stephan et al.
Date published2002
AbstractBottom properties have a major influence upon shallow water acoustics especially for very low frequencies. The use of broadband low frequency signals received on sparse arrays has been shown to lead to robust and efficient estimations of seabed properties. The results of a geoacoustic inversion process both on simulated data and on the INTIMATE'96 experimental data set is presented. The process is based on the use of the measured impulse response on a single hydrophone and aims to build a geoacoustic representation of the bottom which is sufficient to predict acoustic losses for sonar purposes. Firstly the INTIMATE'96 data set is presented. Then the process on simulated data is presented and the validity of the approach is examined. It is then applied to the experimental data set and finally the basis of an equivalent medium concept is derived.
AuthorsJ C Le Gac ; M Asch ; Y Stephan et al.
Date published2002
-
Liquefaction-induced permanent deformantion of embankments on sand deposits by on-line seismic response tests
AuthorsT Fujii ; M Hyodo ; K Fukuda et al.
Date published2000
AbstractRiver dykes and road embankments are often damaged during earthquakes. The main cause is considered to be the liquefaction of the foundations the behaviour of which is not yet fully understood. Based on the results of past studies an embankment's foundation is divided into three areas to examine the failure modes. One-dimensional on-line seismic tests conducted by a combination of element tests and computer seismic response analyses are carried out on areas of actual river dykes damaged by earthquakes. The cumulative lateral displacement values obtained by the tests are compared with the measured embankment-crest settlement data. This shows that the sliding failure due to liquefaction under the toe of slope of such an embankment is the most detrimental of all failure modes.
AuthorsT Fujii ; M Hyodo ; K Fukuda et al.
Date published2000
-
mechanical buckling collapse testing on aluminium stiffened plate structures for marine applications
AuthorsPaik ; Lee ; Ryu
Date published2006
AbstractThis paper summarizes the objectives and some progress of an on-going research project related to mechanical buckling collapse testing on aluminium stiffened plate structures sponsored by Alcan Marine France and Ship Structure Committee USA. unlike stell structures the experimental test data on buckling collapse of aluminium stiffened plate structures is very lacking. Existing test data has mostly been obtained for plate-stiffener combination models or column type models rather than single or multi-bay stiffened panel models with the focus on some specific types of collapse modes. No specific information regarding the fabrication related initial imperfections and softening in the heat affected zone (HAZ) due to welding is found in the literature. To address these issues a research project which involves an extensive test program is on-going under the responsibility of the first author. Design of the test structures and the methods for measuring fabrication related initial imperfrections are addressed in the present paper. Some preliminary results are presented although the test program is on-going and the detailed test results will be reported separately in near future.
AuthorsPaik ; Lee ; Ryu
Date published2006
-
On the effect of bottom profile form of a transom stern on its stern wave resistance
AuthorsTadao Yamano ; Yoshikazu Kusunoki ; Fumiyasu Kuratani et al.
Date published2003
AbstractWhen a ship with a wide immersed transom stern runs on a deeper draft than its design draft forward-oriented wave breaking often occurs just behind the transom. This accompanies large loss of momentum and accordingly large hull resistance. One of the most important factors affecting this is the bottom profile form of the transom stern. However this part of the hull has not been afforded a great deal of attention as it is regarded as only a limited local part of a hull. An analytical method is developed to estimate the effect of the factor on stern wave resistance. Next model tests on typical bottom profile forms are carried out to verify the method and to obtain data for discussion of the effect. Finally characteristics and mechanism of the effect are clarified.
AuthorsTadao Yamano ; Yoshikazu Kusunoki ; Fumiyasu Kuratani et al.
Date published2003
-
Wave loads on a perforated circular caisson and suction pipe of a sea water intake structure
AuthorsK Vijayalakshmi ; S Neelamani ; R Sundaravadivelu
Date published2004
AbstractThe wave force on a seawater intake well model consisting of a perforated circular caisson (500mm diameter) encircling a vertical suction pipe (50mm dia) is measured experimentally. The effect of porosity of the caisson wall incident wave height and wave period on the in-line forces on the caisson and suction pipe is investigated. The porosity of the caisson was varied from 4.54% to 19.15%. Waves of wide ranges of heights and periods were used. The wave forces on the outer caisson & inner cylinder water surface fluctuations in the interior & exterior of the caisson and wave run-up on the outer caisson & inner cylinder are studied. The present paper includes the wave forces on the outer perforated circular caisson and inner circular cylinder due to regular waves only.
AuthorsK Vijayalakshmi ; S Neelamani ; R Sundaravadivelu
Date published2004
-
CFD investigation of the effect of current turbulence on the hydrodynamic forces on a cylinder
AuthorsHyung Taek Ahn ; Yannis Kallinderis
Date published2005
AbstractThe inflow turbulence effect on the hydrodynamic forces exerted on a circular cylinder was investigated by using Reynolds-averaged Navier-Stokes simulations. The range of Reynolds numbers considered was from low sub-critical to supercritical. Time step and mesh resolution studies with various Reynolds numbers were performed for resolution of inflow turbulence. All cases of current profile turbulence were also compared to their corresponding uniform current cases in terms of the amplitudes and frequencies of the forces.
AuthorsHyung Taek Ahn ; Yannis Kallinderis
Date published2005
-
Corrosion in Scotch marine boilers - II. Model boiler tests on the influence of the copper content of the steel on the corrosion of tubes in artifical sea water
AuthorsG Butler ; H C K Ison
Date published1957
AbstractModel Scotch marine boilers containing mild steel tubes of varying copper contents were operated on artifical seawater feedwaters differing in pH and oxygen content. The effects of steel and water composition on tube corrosion pitting and perforation are discussed.
AuthorsG Butler ; H C K Ison
Date published1957
-
Experimental study on the influence of the crest width on the deformation of submerged breakwater
AuthorsSusumu Araki ; Toshihiro Miyazaki ; Ichiro Deguchi et al.
Date published2001
AbstractDesign method in case deformation is permitted has been investigated for rubble mound breakwaters recently. This paper describes the deformation of submerged breakwaters to investigate the process of the collapse and to establish the design procedure in case the deformation is permitted. Classification of deformation change in crest heights influence of core on deformation quantification of deformation and change in hydraulic performances are discussed based on the results of two-dimensional experiments. There was a large difference in the deformed crest heights among the submerged breakwaters with different crest widths.
AuthorsSusumu Araki ; Toshihiro Miyazaki ; Ichiro Deguchi et al.
Date published2001
-
Initial Studies on the Design of a Clamp-On Ultrasonic Flowmeter for Wet Gas Pipelines
AuthorsD Vedapuri ; M Gopal
Date published2000
AbstractThis paper describes the design philosophy of a clamp-on ultrasonic flow meter for wet gas pipelines and discusses the challenges involved in the design. The project goal is to design a meter that will provide both the gas and the liquid flow rate. The liquid flow rate monitor can also be used with conventional gas metering systems to recalibrate meters.
AuthorsD Vedapuri ; M Gopal
Date published2000
-
Regular waves acting on double-layer perforated caissons
AuthorsXuefeng Chen ; Yucheng Li ; Dapeng Sun
Date published2002
AbstractMost experimental analysis and theoretical studies on wave-acting structure interactions concentrate on single-layered perforated caissons with great success. However few studies focus on the double-layered perforated caisson. Here reflection coefficients and total horizontal forces of the double-layered perforated caissons under regular wave action are experimentally investigated. Empirical relationships between reflection coefficients and the ratio of total horizontal forces on the double-walled perforated caissons to those on solid vertical walls with various factors such as the overall relative chamber width the relative water depth and the porosity of the front perforated wall are given. These relationships may be used for engineering applications.
AuthorsXuefeng Chen ; Yucheng Li ; Dapeng Sun
Date published2002
-
Nonlinear Wave Forces on a Marine Pipeline Buried in a Sand Seabed
AuthorsAyman M Mostafa ; Norimi Mizutani
Date published2002
AbstractPipelines are sometimes installed over or in the seabed away from the shoreline. They are used to transport fluids to or from offshore sites and from or to the shore or on a short cut across a bay. Whether the pipe runs over the seabed or is buried in it depends on various conditions including wave and current. In both cases pipes are influenced by wave and current forces but at variable degrees. Here the focus is on the non-linear wave forces acting on a submarine pipeline buried in a sand seabed of finite thickness. The problem is investigated both numerically and experimentally to confirm the validity of results. Analysis is further made for the effect of wave conditions on the wave forces acting on the pipeline. The experiments have been carried out in a 2D wave tank to measure the water surface levels in the pipe vicinity and the pore pressure around the pipe surface. The BEM-FEM model is modified to simulate the wave deformation and the porous flow around the pipeline. The wave forces on the pipe have been computed by integrating the pore pressure around the pipe surface. The results have been compared with the forces computed from pressure measurements in the experiment. Special attention has been given to the effect of wave conditions on the vertical uplift forces in comparison with the horizontal one.
AuthorsAyman M Mostafa ; Norimi Mizutani
Date published2002