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For the design of marine structures including cylindrical components the influence of neighbouring cylinders on the wave loading (interference shelter and amplification effects) cannot yet be estimated with sufficient engineering accuracy. In the Large Wave Channel at the Coastal Research Centre in Hannover wave loads on coastal and offshore structures can be examined at a very large scale thus minimising scale effects. Here large-scale wave experiments were carried out with single vertical and inclined cylinders. Additionally cylinder groups were investigated with special reference to shelter and amplification effects depending on cylinder spacing. Non-breaking regular and irregular waves as well as breaking freak waves were generated. The test set-up and some first results of the experiments looking to the maximum wave loads are reported.

A numerical model is presented in this study to investigate the wave transformation through a submerged permeable breakwater on a porous slope seabed. For this purpose the time-dependent mild-slope equation is newly derived for waves propagating over two layers of porous medium. This new mildslope equation involves the properties of the porous medium and it has the conventional hyperbolic equation form therefore is numerically efficient. The validity of the present model is confirmed based on the comparisons with the previous experiments. The effects of the permeable properties of both the porous seabed and the submerged permeable breakwater are then discussed in detail. The geometry of the submerged permeable breakwater to the wave transformation is also investigated based on the numerical solutions.

Class societies are extending the scope of acommadation comfort guidelines to tackle unwanted noise and vibration in machinery spaces. This article gives details on some of the main guidelines on sound limitations and torsional vibration

The flow around supercavitating hydrofoils is studied. These hydrofoils have cavities which start on the suction side of the foil away from the leading edge (mid-chord detachment) or on the pressure side of the foil in front of the trailing edge (face detachment). This type of cavitation is likely to occur in propellers which are cavitating at design conditions. First the linearised supercavitating hydrofoil problem with arbitrary cavity detachment points is formulated in terms of unknown source and vorticity distributions. The corresponding integral equations are inverted analytically and the results are expressed in terms of integrals of quantities which depend only on the hydrofoil shape. These integrals are computed numerically in an accurate and efficient way to produce cavity shapes and pressure distributions on the foil and cavity. He effect of the cavity detachment points on the shape of the cavity and the foil pressure distribution is investigated. An inviscid flow criterion for the cavity detachment point is derived for the case where the cavity detaches in front of the trailing edge on the pressure side of the hydrofoil. Finally the accuracy of the linearised cavity theory is assessed for different foils and flow conditions by analysing the produced cavity shapes with a non-linear panel method. Conclusions are drawn and future research is identified.

Lubricants are essential design elements in the complex systems of marine diesel engines. It is essential that designers of marine diesel engines and of marine lubricants should co-operate to design an interface between engine and lubricant for the benefit reliability and efficiency of the entire system. The WG (working group) 'Lubricants' was established in 1987 with the aim of generating a user language on the lubrication of large diesel engines and on the technology of designing and using lubricants and lubrication systems. It is described how this WG was established and how it was able to develop its structure working style methods and its unique efficiency. Current work is on the treatment of lubricants an update of Recommendation Number 13 the impacts of emission controls and the lubrication of engines running on non-standard fuels. Work published and recommendations-guidances given by this WG through publication has been positively received by the industry and is used as a reference within the industry (users operators) and. A future key problem will be the lubrication of marine diesel engines running for prolonged periods on LSFO (low sulphur fuel oil). This and the inflammability of lubricant-fuel vapours in the crankcase will need a dedicated input from all members. WG concentrates on core tasks team and networking and leaves jobs others can do to them. This has enabled the WG to work successfully and this style should ensure that they remain successfully.

In December 1980, IEA Ministers decided that publication of more comprehensive information on historical trends and prospects for coal use, production and infrastructure development would help to reduce uncertainties constraining the role of coal in the IEA energy system. Based on recommendations form the Coal Industry Advisory Board, identification of information needs and review of available information, a decision was reached to implement a comprehensive IEA Coal Information system. This was intended to provide both IEA Member countries and those employed in all sectors of the coal industry with information on current world coal market trends and long-term prospects. This is the fourth publication based on the IEA Coal Information System. It differs from the previous one in that the IEA has improved on the concept of 'solid fuels' by separating out coal from all other primary solid fuels. It includes data on coal reserves, production, trade, demand, prices, transport infrastructure, coal-fired power stations and for the first time, emission standards for coal-fired boilers. Part 1 provides an overview of world coal market developments and prospects and Part 2 provides, in tabular form, a more detailed and comprehensive picture of coal developments and future prospects for the OECD by regions and countries.

A computational tool was applied based on a two-dimensional linear method to predict the hydrodynamic loads for damaged ships. Experimental tests on a ship model have also been carried out to predict the hydrodynamic loads in various design conditions. The results of the theoretical method and experimental tests are compared to validate the theoretical method. The extreme wave-induced loads have been calculated by short-term prediction. For the loads in intact condition, the prediction with a duration of 20 years at sea state 5 is used, while for loads in damaged conditions, the prediction with 96 hours of exposure time at sea state 3 is used. The maximum values of the most probable extreme amplitudes of dynamic wave-induced loads in damaged conditions are much less than those in intact condition because of the reduced time. An opening could change the distribution of not only still-water bending moment but also wave-induced bending moment. It is observed that although some cross-sections are not structurally damaged, the total loads acting on these cross-sections after damage may be dramatically increased compared with the original design load in intact condition.

North Carolina has more than 2500 square miles of land within one meter of spring high water. Despite the State's vulnerability it has few policies that deal directly with the economic and environmental ramifications of sea level rise. The State does have policies that require oceanfront setbacks for new development based on historical erosion rates and coupled with this there is a prohibition on hardened-permanent erosion control structures on ocean beaches and inlets. However along the estuarine shoreline policies regulating development are far fewer. In 1999 the State established a buffer zone along much of the State's coastal rivers and estuarine shoreline. Although this buffer may delay some of the impacts of rising sea level the primary motivation for action was water quality protection - not protection from sea level rise or storm events. Finally the State's CAMA (Coastal Management Act) requires land-use planning in the State's 20 coastal counties and the State's planning guidelines require local governments to address the issue of sea level rise. However most of the current plans only lightly touch on the issue and defer action to the state's coastal management program. This study develops maps depicting three shore protection scenarios that reflect potential responses to sea level rise. The three scenarios are based on alternative policy responses to sea level rise. The scenarios are visually depicted on 12 maps (technically not feasible to present them in the conference materials). Creating these maps required existing coastal policies to be analysed and interviews to be carControl No

Quantifying the fatigue crack growth and remaining life in joints making up jacket structures forms one of the basic requirements of a sub sea structural integrity assurance scheme. The accurate prediction of the likely failure time of welds allows a realistic estimate of the risk of structural collapse at any stage in a structure's life. It is current practice to consider the welds making up the member as individual components rather than looking at the whole compliant system of welds joints members and structural framing arrangement. In this approach the nominal loads in any one member are determined from an analysis of the undamaged structure and are then applied to a crack growth solution using handbook stress intensity factor solutions to determine the fatigue life of that component. This method assumes that the applied load is purely load-controlled whereas in reality it is a combination of both load and displacement controlled. A study was carried out to investigate the influence of the surrounding structure on crack growth in tubular members located in jacket structures. The aim of the study was to verify whether the traditional approach which uses stresses from undamaged structures to evaluate crack growth in individual components is appropriate. The findings of the study showed that structural compliance has only a beneficial effect on fatigue growth in the latter stage of the crack growth process with crack lengths greater than 40 percent circumference. It was shown that the beneficial effect of structural compliance on fatigue crack growth in the later100254 Effect of structural member uncertainties in the jacket-type offshore platform assessments

The movement of offshore gas transportation pipelines to deeper and deeper waters has generated new challenges. In order to reach depths greater than 2000 m even with X70 grade wall thicknesses of nearly 30 mm are required for 24-inch diameter line-pipe. The resulting lay tension requirements on the pipe-laying vessel are enormous. For this reason any ability to reduce the pipe wall thickness and still resist the external pressure at these depths would be quite attractive. Line pipe is often coated prior to installation in order to achieve some protection against the environment. Many of the coatings used today require the pipe to not only be cleaned and degreased but also to be pre-heated to a temperature of 200-240 degrees C during application of the coating material. A typical coating thermal cycle involves rapid heating of the pipe using induction coils application of the coating and quenching to cool the pipe for handling purposes. It is generally understood that this thermal treatment on UOE line pipe which can last from a couple to as many as ten minutes has an effect on the pipe yield and to a lesser extent tensile strength. For ultra-deepwater offshore applications where collapse is often the controlling design case the increase in hoop-compressive yield strength is viewed as desirable because of the corresponding increase in collapse pressure. For onshore applications however bending due to differential ground movements can be the primary design consideration. In this case

A rectangular barge model is prone to capsize in a beam sea under regular waves with a wave period the same as the natural period of the barge roll motion when the barge freely floats in a 2D wave tank. The general trend to study ship motion forced by waves is to measure the corresponding motion of ship against incident waves. With the help of PIV the quantitative flow information and flow pattern as well as the ship motion can all be captured. The purpose of this study is a preliminary investigation of the flow structure around a fixed rectangular barge interacting with regular waves. This is the fist step in the study of interactions between the waves and the rectangular barge motion for better understanding of the capsizing mechanism. The present study can be extended to the analysis of the flow characteristics in the vicinity of a floating breakwater. An experimental study on wave interactions with a rectangular barge in a beam sea condition is presented. Regular waves with a wave period the same as the natural frequency of the barge were used in the experiments due to the fact that the barge is prone to capsizing under such waves. The barge was fixed on the free surface and no wave overtopping was assumed. PIV (particle image velocimetry) was used to measure the full-field 2D velocity. As the flow is highly turbulent the phase-averaging technique was used to the extract the mean flow and turbulence properties. The mean flow pattern including velocity vorticity and streamline was analysed to quantify the mechanism of the interactions. The generation and evolution of vorticity and turbulen102369 Experimental study on wave loads of flooded ship

In the Arctic region the ice forces in most cases determine the design load level for offshore structures. The ice forces on structures depend on many factors some of them relate to the ice itself and some to the structure. The geometry type of ice features and its physical and mechanical properties are the most important factors that affect ice load. Several methods were developed for ice load calculation. The most common approach is based on the Korzhavin's method where the load is determined by multiplying the uni-axial compression strength of the ice on several coefficients describing both the structure and the ice field. Therefore it is important to made a proper analysis of the ice strength evaluation. Experimental studies of ice strength variability in relation to different length scales were carried out on landfast level ice on Svalbard (Norway). The step (horizontal distance) between ice samples was continuously reduced in order to find out how the ice strength variability develops. The spatial variation of the physical properties of the ice such as temperature salinity density was measured. The typical ice strength variability for the areas larger than 40 m2 was found to be about 20 - 30 % for the vertical ice cores of the certain depth from the ice cover surface. For the horizontal ones it was slightly less - about 10 - 20 %. Firstly the ice strength heterogeneity in relation to different length scales is considered and it is proposed that ice strength variability should decrease with reduction of length scale. Test programs are carried out in ord100103 In-situ uniaxial compression tests of level ice. Part 2: ice strength spatial distribution

A site investigation has been performed for bridge abutments constructed on soft ground which are deformed laterally by backfill. In order to prevent lateral movement of bridge abutment the pile slab is proposed as a countermeasure. This method can effectively prevent the lateral flow of soft ground since the overburden surcharge due to backfill on soft ground would be effectively delivered to bedrock through the piles in soft ground. This study consists of field investigation evaluation of lateral movement of bridge abutment and presentation of its countermeasures. The result of this study illustrates that the abutment foundation piles should be designed as not only the active pile but also the passive pile.

A feasibility study on tidal current power generation in Kanmon Strait Japan is introduced in this report. A variable mesh version of the Marine Environmental Committee ocean model is used to reproduce the tidal current and to learn the distribution of tidal kinetic energy. Based on the simulation results the optimal location for installation of a power plant is determined. The electric power created by a propeller type generator with a 10m diameter is also calculated as the average annual consumption of a household and availability of the power generation by the tidal current in Kanmon Strait is discussed.

A fatigue crack growth model based on cumulative damage is presented when a material element ahead of the crack tip is approached by the tip of the crack. The cyclic plastic zone and process zone ahead of the crack tip are taken as the area where damage accumulation takes place when the material element first enters into the cyclic plastic zone and then into the process zone. During this period the Coffin-Manson damage law in conjunction with Miner's linear damage accumulation is used to determine the damage in the material element. A constant strain gradient is assumed along the process zone ahead of the crack tip and the size of process zone is taken to be variable and dependent on the range of stress intensity factor. For a cyclic loading the effective crack driving force takes into consideration the crack tip blunting process. The model results are in good agreement with experimental data available in literature for a number of materials.

A primary production algorithm is presented which is under development for inland waters. This is based on remote sensing data and is being developed in Lake Constance. A widely used open ocean primary production model is adjusted to the conditions in inland waters by combining experimental data and sensitivity analyses. Main factors influencing the primary production are the chlorophyll concentration near the surface light temperature depth of the mixed layer vertical distribution of water constituents primary production parameters and phytoplankton taxonomic composition. Once the European Satellite ENVISAT is in orbit the sensors on board will be used in synergy for the determination of chlorophyll and temperature derived from optical and thermal data. Results from the data analysis are presented.

This paper considers the effects of marine exposure and cathodic protection on the corrosion fatigue and hydrogen embrittlement of high strength offshore steels. It examines the extent to which sulphate reducing bacteria in the marine environment promote the uptake of hydrogen by cathodically protected steel. The effects of this absorbed hydrogen on embrittlement of the steel under static loading and the enhancement of crack growth rates in corrosion fatigue are described. The threshold conditions for corrosion fatigue are discussed and a method is proposed for selecting safe levels of cathodic protection for high strength steels in a range of environments.

The relation between the shape of slope and bearing characteristics in an oil-lubricated aft stern tube bearing is examined. In this bearing slope is usually provided to decrease the locally distributed load (from the cantilever weight of the propeller) on the aft part of the bearing. Three kinds of shape of slope (single partial and double) are considered together with three kinds of calculation method (simple spring and oil-film support). The shafting used in the study is an ordinary type directly driven by diesel engine and provided with aft and fore stern tube bearings and one intermediate shaft bearing. The calculation method is described detailed results are given and conclusions are drawn. Shape and dimension of slope and results of calculations are all given in graph format on pages 166-168.

A time domain solution for interaction of large amplitude incident waves with free-surface piercing fixed structures is presented. The solution is based on an integral relation formulation coupled with time-integration of the free-surface and other boundary conditions similar to a full nonlinear MEL scheme. On the assumption of smallness of perturbation effects the diffraction (and radiation) problem is linearized which reduces the computational count drastically compared to the full nonlinear solution. The incident wave considered is nonlinear and the body-condition applied on the mean surface is based on this nonlinear potential. Results presented for circular cylindrical structures demonstrate that it is possible to get a few periods of steady-state force and moment time-histories depending on the size of the computational domain. Computations performed for a 3D semisubmersible geometry demonstrate that the method can be applied to 3D offshore structures of complex and practical shapes.

TDP ; VIVMS ; vortex induced vibration The TDP (touch down point) monitoring system is presented. This was established to evaluate and verify methodologies and to calibrate the numerical models used in a riser mooring system and platform design. It is used to monitor all the relevant parameters (environmental platform positions and motions riser loads and stresses at the top and at the TDP and vortex induced vibrations). Also presented is VIVMS (vortex-induced vibration monitoring system) which was added to measure and record vibrations of the SCR-induced by flow and by the motions of the semi- submersible platform P XVIII. VIVMS is described. It was developed to measure at up to four locations along the SCR accelerations in three orthogonal directions and angular rates in two directions. The system records this information locally in subsea enclosures transmits it to the surface on command and includes the software to transform the riser fixed accelerations and rates to earth fixed linear and angular velocities and displacements. Graphs diagrams and photographs appear on pages 8 to 11.