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Model experiments of hydrodynamic forces on heave plates
AuthorsKie Hian Chua ; David Clelland ; Shan Huang et al.
Date published2005
AbstractFor truss SPAR platforms damping plates are used to increase the added mass and viscous drag in the heave direction. This paper aims to investigate experimentally the hydrodynamic forces on heave plates with different opening sizes. Model scale experiments were carried out on three 40 by 40cm flat plates to investigate the effects of oscillation amplitude and opening size on the hydrodynamic forces acting on the plates whilst undergoing forced heave motion. Three different methods of data processing were investigated namely directly processing unfiltered data to obtain the hydrodynamic coefficients filtering the data before evaluating the coefficients and fitting the filtered data to a sine curve before evaluating the coefficients. The most accurate method was then selected and used to evaluate the experiment results. The coefficient values obtained were compared with the published data available. The effects of various variables such as opening size KC number and frequency of oscillation on the hydrodynamic coefficients were also studied. Relative magnitudes of the drag and inertia components of the overall hydrodynamic load are compared.
AuthorsKie Hian Chua ; David Clelland ; Shan Huang et al.
Date published2005
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On the mathematical modelling of the manoeuvring of inland vessels by consideration of the current influence on their manoeuvring behaviour
AuthorsPeter Kolarov ; Mathias Paschen
Date published2006
AbstractA vessel manoeuvring on an inland waterway is restricted by the riverbanks and the river's winding course as well as by the riverbed and the water depth. The size and velocity of inland vessels is growing rapidly and this affects the development and maintenance of inland waterways. Numerical simulations are suited to analyse numerous case studies of ship's motions under different random conditions in advance. This should lead to an improvement in the necessary expertise to minimise the risk for vessels as well as for the environment. Results of numerical and experimental analysis of ship motions are presented with consideration of river current and water depth. Mathematical models for the determining the influence of variable current environments on the manoeuvring behaviour are presented and validated by model tests. Some applications of the mathematical model are also presented. Theories and experiments are shown to have good agreement.
AuthorsPeter Kolarov ; Mathias Paschen
Date published2006
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On the structural analysis of the staggered multi-hull
AuthorsTommaso Coppola
Date published2005
AbstractIntensive research into multi-hulls for both naval and commercial applications involves hydrodynamic and sea-keeping analyses; however little research on loads building and structures has been developed. Multi-hulls for small and medium-size have been realised for naval applications. Now researchers and designers are analysing small- and medium-sized multi-hulls for commercial and tourist applications on short routes and larger multi-hulls carrying containers on trans-oceanic routes. In recent years displacement hulls for intermediate Froude Numbers Fn < 0.6 have been studied. Among the solutions tested multi-hulls both symmetric (catamarans and trimarans) and asymmetric (staggered catamarans) seem to be quite interesting. The small amount of available experimental data for staggered catamaran in particular led to a research program using a towing tank to evaluate the relation between the total resistance of the ship the stagger of demi-hulls and displacement. A study is presented considering the hypotheses on which the design formulas of the classification societies are based for the determination of the transverse global loads for catamarans. Simplified methods are proposed for calculating loads and loads effects on a catamaran staggered fast ferry. The method
AuthorsTommaso Coppola
Date published2005
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Simulation of ice accumulation on transmission line cables based on time-dependent airflow and water droplet trajectory calculations
AuthorsPing Fu ; Gilles Bouchard ; Masoud Farzaneh
Date published2004
AbstractThe Local Collision Efficiency (LCE) is a key parameter for ice accretion simulation since it describes the distribution of droplet impingements on the surface of an object. In this paper a numerical procedure is introduced to calculate airflow and water droplet trajectories which were used to evaluate the LCE in the newly developed ice code. Also the validity of several approaches and approximations for determining LCE in the context of atmospheric icing is studied. This paper also examines the influence of the droplet spectrum on the collision efficiency.
AuthorsPing Fu ; Gilles Bouchard ; Masoud Farzaneh
Date published2004
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The effect of wind and wave misalignment on the response of a wind turbine at Bockstigen
AuthorsJenny M V Trumars ; Johan O Jonsson ; Lars Bergdahl
Date published2005
AbstractThis work evaluates data from the offshore wind farm Bockstigen in order to study the effect of directional spreading of waves and wind wave misalignment on the response of the structure. The development of offshore wind energy has led to wind farms at sites with water depths ranging from approximately 6 to 30 m. The change of location from land to sea changes the design requirements of wind energy converters. In addition to wind loads the wave load on the structure has to be taken into account. Since a wind turbine is highly damped in the inline direction as compared to the crosswise direction the effect of directional spreading of waves on the response is studied. Depending on the dynamics of the structure the crosswise force could give a larger response than the corresponding inline force. In this study the influence of the directional spreading of the waves on the response is not clear however the effect of wind and wave misalignment is clear.
AuthorsJenny M V Trumars ; Johan O Jonsson ; Lars Bergdahl
Date published2005
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The Government response to the House of Lords Select Committee on Science and Technology report on safety aspects of ship design and technology
Authorspresented to Parliament by the Secretary of State for Transport
Shelf Location227f
AbstractThis paper responds to the recommendations of the House of Lords Select Committee Report on Safety Aspects of Ship Design and Technology and outlines the Government's view on the applicability of the safety case concept to the shipping industry internationally. It is divided into two parts. Part I contains the chapters "Shipping and the Safety Case Concept (Government Response to Recommendations 12.1, 12.2 (iv) and 12.2 (v)); and End Notes to Shipping and the Safety Case Concept. Part II covers Government Response to Other Recommendations (Recommendations 12.2.(i)-(iii), 12.2(vi)-12.4))
AuthorsPublisherpresented to Parliament by the Secretary of State for Transport
London : HMSO, 1992.
ISBN number101212127
Shelf LocationDate published227f
1992
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You ain't seen nothing yet (Bachman Turner Overdrive) - new advice on shore protection for Great Lakes property owners
AuthorsPhillip Keillor
Date published2001
AbstractIn 1973 the US Army Corps of Engineers published a pamphlet called Help Yourself. This pamphlet described erosion problems on the Great Lakes and showed alternate methods of shore protection (principally structures). However new knowledge and experience have made the old pamphlet obsolete. Lakebed erosion on cohesive shores is now recognised as a threat to virtually all types of shore protection structures. Freeze-thaw action on armor stone is now recognised as a common cause of structural failure on stone structures across the world's northern temperate zone. New advice on shore protection for Great Lakes property owners and contractors is presented that is contained in a draft replacement booklet. The booklet contains a new primary message and fresh insights from a group of experts convened in August 2000. The new recommended approaches to coastal risks of erosion and flooding are in the following order of choice: adaptation restoration moderation and armoring (a choice of last resort). These approaches follow those taken in the Corps of Engineers' new Coastal Engineering Manual.
AuthorsPhillip Keillor
Date published2001
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A guide to the Offshore Installations (Safety Case) Regulations 1992: guidance on regulations
AuthorsHealth and Safety Executive
Shelf Location227c
AbstractThis publication provides guidance on the Offshore Installations (Safety Case) Regulations 1992. After the introduction, the text of each regulation and schedule is given in italics followed by guidance on it. A concluding section of the publication sets out more detailed guidance on the preparation of safety cases as required under the Regulations. The primary aim of the Regulations is to reduce risks to the health and safety of the workforce employed in offshore installations or in connected activities.
AuthorsPublisherHealth and Safety Executive
London : HMSO, 1992.
Shelf LocationDate published227c
1992
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A laboratory simulation of wet icing build-up on H V insulators
AuthorsM Farzaneh ; J-L Laforte
Date published1997
AbstractA practical laboratory method is proposed to simulate wet atmospheric ice accretion on HV insulators. The method is based on first accumulating a low density soft rime on energized insulators and then heating the produced deposits. The liquid water fraction of the ice accretion is determined using a centrifuge. The performance of insulators under wet snow-like conditions with relatively low cost equipment can be determined.
AuthorsM Farzaneh ; J-L Laforte
Date published1997
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A risk-based approach for the evaluation of fire & safety equipment on liquefied gas jetties
AuthorsR J Roue
Date published1998
AbstractThe development of a document in which quantitative risk assessment (QRA) is used to determine the effectiveness and requirements for fire fighting equipment on jetties has been carried out by AEA Technology on behalf of SIGTTO. Objectives theoretical background and the principles of QRA are explained and a simplified overview of the risk based approach for the evaluation of fire and safety equipment on LPG jetties presented.
AuthorsR J Roue
Date published1998
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An investigation of ballast water management methods with particular emphasis on the risks of the sequential method
AuthorsLefteris Karaminas
Shelf Location226b
AbstractThe objectives of this study on ballast water management are: to investigate the effects of the one of the IMO ballast water exchange at sea methods, the sequential method, on the ship’s structure and the assessment criteria in respect of classification, statutory and operational aspects; and to develop a safe operational envelope, on the basis of sea-keeping analysis, to control the dynamic effects for the ballast condition under consideration.
AuthorsPublisherLefteris Karaminas
Lloyd's Register
Shelf LocationDate published226b
2000
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Changing technologies - implications for personnel on naval platforms
AuthorsL A Kemp ; Colin Corbridge ; A O'Shea
PublisherIMarE Conferences and Symposia
AbstractWork conducted by the Defence Evaluation and Research Agency (DERA) Centre for Human Sciences (CHS) to examine the effects of lean manning and increasing technology on the Royal Navy (RN) organisation is described. First a look is taken at skill requirements platform organisation and branch structure problems. After this two studies carried out to investigate the impact of new technology on the personnel organisation on a frigate sized naval platform are described and discussed.
AuthorsDate publishedL A Kemp ; Colin Corbridge ; A O'Shea
2000
PublisherIMarE Conferences and Symposia
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Climate change and its effects on coastal management
AuthorsAlan H Brampton
Date published1996
AbstractThe observed or deduced changes in both the hydraulic and sedimentary regime of the UK coastline is examined and some case histories are presented. After some introductory information attention is given to effects on coastal management in view of recorded climatic changes and the widely expected continuation of global warming. Next a look is taken at effects of changes in wave climate including impacts on man-made defences and impacts on beaches. This is followed by consideration of other effects covering rainfall changes in winds and temperatures in water temperature.
AuthorsAlan H Brampton
Date published1996
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Effect of soft root weld layer on fracture toughness of under-matched weld joints on Q+T steel
AuthorsI Rak ; V Gliha ; Z Praunseis et al.
PublisherThe American Society of Mechanical Engineers - ASME
AbstractSamples of quenched and tempered high-strength low-alloy steel (HT 80) were multipass welded to give undermatching homogeneous or heterogeneous welds with soft root passes: impact toughness and CTOD (Crack Tip Opening Displacement) were determined and correlated with joint characteristics.
AuthorsDate publishedI Rak ; V Gliha ; Z Praunseis et al.
1996
PublisherThe American Society of Mechanical Engineers - ASME
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Effects of hull length on the hydrodynamic loads on a slender underwater vehicle during manoeuvres
AuthorsC D Williams ; T L Curtis ; J M Doucet et al.
Date published2006
AbstractExperiments were performed with the bare hull of a full-scale slender body-of-revolution underwater vehicle of five different lengths using an internal three-component balance and a planar motion mechanism (PMM). The experiments included resistance static yaw dynamic sway and yaw and circular arc runs. Results from the resistance static yaw and sway runs are presented.
AuthorsC D Williams ; T L Curtis ; J M Doucet et al.
Date published2006
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Effects of Soil Information on Economics of Jackup Installation
AuthorsD A Geer ; S D Devoy ; V Rapoport
Date published2000
AbstractThe economic impact of quality and availability of site soil information on safe jackup installation is looked at. Preload operations based on sufficient and on limited (or insufficient) soil data are analyzed. Reliability and applicability of a variety of soil information sources are discussed. The time to preload can be significantly reduced if sufficient soil information is available.
AuthorsD A Geer ; S D Devoy ; V Rapoport
Date published2000
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Experience of the Indian Ocean Tsunami on the Sri Lankan coast
AuthorsS Hettiarachchi ; S Samarawickrama
Date published2005
AbstractA summary of the initial efforts in understanding the Indian Ocean Tsunami and its hydraulic impact on the coastline of Sri Lanka. Attention is focused on the hydraulic processes which led to large scale inundation analysis of wave-current measurements recorded offshore of Colombo Harbour and describes post tsunami field investigations to assess the overall impact on the coastline. The need for modelling potential tsunamis is identified and issues relating to the planing of countermeasures briefly discussed.
AuthorsS Hettiarachchi ; S Samarawickrama
Date published2005
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Experimental study on static strength of corrosive mild steel
AuthorsM Oka
Date published1990
AbstractA paper confirming that corrosive mild steel members in some cases show a decrease in ductility that is elongation. Furthermore it has been found that this phenomenon has been brought about by corrosive pits formed on their surfaces. The effects of corrosive pits on static strength have been studied parametrically by the simulation test in which artificial pits are formed on the surfaces of test specimens.
AuthorsM Oka
Date published1990
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Hydrodynamic forces on a submerged plate
AuthorsMikio Takaki
Date published2001
AbstractIn this paper numerical simulations are created to make clear the mechanism of hydrodynamic characteristics on the submerged horizontal plates by applying the Marker and Cell method (MAC method). First the numerical method is validated by comparing it with the experimental results. Then the flow field around the submerged-plate is discussed by using the numerical results. Finally the transmission wave coefficient and the hydrodynamic forces and moments acting on the submerged-plate are estimated and the effect of inclination of the submerged-plate on them is discussed.
AuthorsMikio Takaki
Date published2001
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Ice and earthquake loads on a structure in the Okhotsk Sea: annual report of the JOIA project FY1998
AuthorsK Kato
Date published2000
AbstractJOAI (Japan Ocean Industries Association) has been organising the research project 'Study on Ice Load Acting on Marine Structures' since 1993. The research was undertaken because it was recognised that cold regions especially ice-covered waters were recognized as regions which were important for future developments of natural energy resources. In this paper the main outcomes of the studies during FY1998 carried out by the project are briefly described. In addition on-going studies are briefly introduced.
AuthorsK Kato
Date published2000