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The effect of water deluge on gas dispersion is addressed. Experimental research on the effect of deluge on gas dispersion is described. After this CFD simulations of selected tests using FLACS are presented. Then CFD predictions are compared to gas detector recordings from an actual offshore incident. Finally it is concluded that deluge may have a significant effect on gas dispersion as seen through medium-scale experiments as well as through full-scale real leak situations. It is suggested that risk studies for installations for which use of deluge is a likely procedure in gas leak situations should include the modelling of the effect of deluge on dispersion.

A new more exact approach for the problem of impact interaction of a ship structure (ship's frame) with compressible water domain which allows taking into account the structure flexibility is presented. The influence of the ship structure flexibility on hydrodynamic impact loads is studied. In result it is possible to specify better the external loads on the ship structures.

The purpose of this paper is to review the worldwide historical structural failure data in the 1990s on offshore structures and compare this with the present risk analyses of Norwegian offshore structures. The paper describes an overview of registered accidents to offshore structures based on the databases WOAD and CODAM. The accident data is given for fixed platforms jack-ups and for floating platforms. Estimates of risk level in annual frequencies and PLL values are given for each platform type.

This paper reports on an investigation into the influence of slamming and whipping on the fatigue life of a large high-speed catamaran. Full-scale measurements of slam events were conducted on a 98m Incat catamaran to investigate its slamming behaviour in a variety of sea conditions. The full scale results were then used to determine the influence of the presence of slam events on fatigue life. In addition the effects of significant wave height slam occurrence rates slam peak stresses and whipping behaviour on fatigue life were examined.

More than 50 per cent of ship operating expense is the cost of the fuel. The fuel oils used in marine power plants are therefore generally of degraded types in order to conform to the demands of ship owners for economy. These marine fuel oils are composed mostly of multi-components and immiscible matter such as ash carbon residue and water. The literature provides abundant studies on the combustion of single components or miscible multi-component liquid fuels. However the number of studies on degraded heavy fuel oils is rather small. An experimental study carried out on a single oil droplet suspended on a quartz filament is carried out to investigate the effects of droplet size and heating time on the combustion characteristics of marine fuel oils. Fuel oils A and C which approximate ASTM numbers 2 and 6 fuel oils respectively are considered in this study primarily due to their frequent applications in marine power plants. The properties of these fuels are widely different; marine diesel oil A is a distillate oil of miscible multi-components while heavy fuel oil C is known as a residual oil containing considerable amounts of immiscible matter.

Ship service electrical power consumption at the pier side is rapidly growing and now exceeds 10 megawatts (MW) power range on many of the latest commercial ships. These ships when docked at the ports consume hotel power produced by on-board generators resulting in air pollution. The environmental impact of the pollution created while at berth has many ports restricting the operation of these on-board generators. Shutting off these on-board generators and supplying ship's hotel power from the shore power system can reduce the air pollution emissions. This process when shore power is provided to the ship during berthing by shutting down its generators is called cold ironing. For limited power supply this technology has been used by the military at naval bases for many decades when ships are docked for long periods. However with the development of medium voltage power plugs and receptacle assemblies cold ironing projects existing applicable standards for ship interconnections to shore power and proven techniques for shore power interconnections. The paper will highlight the main features of a cold ironing power system with emphasis on personnel and equipment protection by an alternate electrical grounding system. the paper also describes an actual cold ironing project in which a barge is used to mount a unit substation and cable management equipment.

Wave and current loadings on offshore pipelines are a major design concern. The forces exerted by the environment may result in pipeline failure when the design limits are exceeded. For economical and practical reasons many offshore pipelines are accompanied by a smaller diameter service line or umbilical to create a bundle. This gives rise to the so-called piggyback configuration. The flow behaviour around the bundle is not well known leading to concerns on the stability of the configuration. The influence of the piggyback on the hydrodynamic loadings on the bundle in wave plus current condition using CFD (computational fluid dynamics) is investigated. Key parameters of the configuration that were investigated were the orientation of the smaller pipe with respect to the main pipeline and the flow conditions (different Keulegan-Carpenter numbers). The gap between the seabed and the main pipe was set to zero for all cases investigated. It was found that the hydrodynamic characteristics of the main pipe were significantly influenced by the presence of the piggyback. The numerical results also showed that the orientation of the piggyback plays an essential role in determining the drag lift and inertia coefficients for the bundle. This phenomenon is explained by examining the vortex flow patterns around the cylinders. It is shown that the established industry practice of assuming the hydrodynamic characteristics of the bundle to be the same as an equivalent diameter cylinder may underestimate the forces on the bundle and lead to a non-conservative design.

The principal objective of this book is to provide a modern treatment of graphics and an introduction to conceptual design so that graphics can be employed to the synthesis, analysis, and solution of problems that arise in the fields of design, development, and research. Part 1, Fundamental Principles and Applications o Orthogonal Projection, lays stress on principles. Rote learning is discouraged. Thorough grasp of the few fundamental principles will greatly enhance the students’ ability to think through and solve various space problems that arise in both engineering and science. Emphasis is on thinking not on draftsmanship. Interesting examples of the application of the fundamental principles of orthogonal projection to problems that have arisen in the field of research are included. Chapter 11, the final chapter of Part 1, is intended to strengthen the students’ ability in analysis. Part 2, Graphical Solutions and Computations, includes the graphical presentation of data; graphical mathematics – arithmetic, algebra, calculus; empirical equations (forms most frequently encountered in engineering); functional scales; and an introduction to namography. Part 3, Introduction to Conceptual Design, affords the student an opportunity to be on his own. His background in graphics – based on the material in the first two parts – coupled with his course work in mathematics, chemistry, physics, and perhaps some actual job experience will have a direct bearing on his progress in dealing with projects that have many solutions. The chapters on pictorial drawing, sections and conventional practices, fasteners, dimensions and specifications, dimensioning for precision and reliability, constitute additional background material for the chapter on conceptual design.

Emissions limits have been placed on almost every size and type of internal combustion engine in order to reduce greenhouse gases eliminate acid rain and improve the quality of the air in major metropolitan areas around the world. Within the electrical power generation marketplace there is growing demand for spark-ignited engines capable of running on fuels with low or varying energy content. In addition to the non-traditional fuel applications there is a desire to improve efficiency and to push the transient performance envelope of these low emission power plants. The development of the next generation of integrated electronic genset control systems is one key to addressing any of these challenges. Historically new control system software development was an expensive and time consuming process that involved many iterative cycles and detailed information exchanges between engineers with all the associated potential for confusion and miscommunication. Algorithms were coded and tested using production engine control units which limited the ability to explore new control schemes using new sensor sets and required the involvement of many different individuals to test debug code compile and document software changes.

The coastline of the province of Naples extends more than 150 km. The provincial Civil Protection evaluates the potential risk of flooding on the beaches and establishes a database of beaches vulnerable to wave storms so that a priority scale of possible shore protection measures could be established and individual projects could be managed within a single framework covering benefits as well as adverse impacts. A regional modelling system encompassing winds waves and evaluation of risk of beach flooding is the backbone of the planned Civil Protection shoreline management system. The wave component of the comprehensive regional modelling system is described. The focus is on wave modelling and substantiates the model implementation on the coastline of the province of Naples and the model validation through a statistical comparison with wind and wave data collected on the Northern and Southern boundaries of the Gulf of Naples. The spectral third-generation wind-wave model Wavewatch 3 was adopted for simulating wave propagation and risk evaluation in the Gulf of Naples. The results are used to classify the coastal zones of the province of Naples on the basis of the risk evaluation.

The development of mathematical models numerical methods and parallel algorithms for aerodynamic design problems focusing on multi-processing and computing systems is considered. Numerical methods of calculating 3D flows are considered within the framework of full unsteady Navier-Stokes equations as well as sub-models from the point of view of parallel calculations. Numerical methods are based on a finite-difference finite-volume method and also Godunov's schemes. The codes provide a mathematical modelling of unsteady 3D flows near geometries of the real form. Use of technology of parallel calculations on multi-processing computer facilities will proceed a qualitatively new approach at the solution of aerodynamic designing problems. One of the basic problems is the grid regeneration that takes into account geometrical and physical features of flow field. The physical region is divided on sub-regions and within each sub-region a structured grid is generated. One method of 3D generation based on marching procedure of parabolic generator is presented. A grid adaptation strategy is included in flow field simulation. Structured meshes are adapted to the flow gradients in boundary layers wakes solving the shocks etc. The CFD problem is solved using a decomposition domain improving communication between processors and using standards from the MPI (message passing interface) system. The choice of MPI as a library is determined by the requirements that the resulting prograX14754

The use of water to prevent NOx formation during the combustion process is now well documented. The HAM system (humid air motor) is presented. HAM is a promising method for reaching this target. This method evaporates large quantities of water after compressor outlet of the turbocharger. The aim is to get the charge air close to saturation. The performance and self-regulating ability of HAM has been extensively tested on a 3-cylinder PC 2.6 B engine of Pielstick. Other tests have been carried out on small Scania engines. All the tests have confirmed that HAM can reach a NOx reduction of up to 70 per cent using heated water for evaporation. Based on these excellent results HAM was installed on one of the four 12 PC 2.6 propulsion engines of the Viking Line ferry Mariella. The operating results of this system are presented and are very satisfying. After 6000 operating hours a HAM system has been ordered for all four of Mariella's 12 PC 2.6 propulsion engines. The system was started up in July 2001 and has been operating satisfactorily with no impact on engine behaviour. An independent test company has carried out measurements and has confirmed a NOX reduction of 70 per cent. Seawater has been used for the humidification process which results in negligible operating costs.

First Int Conf held in Norway 2 - 5 August 1976 Papers are Waves and wave forces Foundation engineering for fixed offshore structures Behaviour of structures and structural design The calculation of steep gravity waves On wave groups Interactions between waves and currents and their influence on fluid forces Parameterisation of wave spectra and long term joint distribution of wave height and period Prediction of extreme wave induced loads on ocean structures Wave loads on structures Vortex shedding and resistance in harmonic flow about smooth and rough circular cylinders Critical review of drag and inertia coefficients for offshore design Wave loads on pipelines on the sea floor Motions of offshore structures as influenced by mooring and positioning systems The suppression of structural vibrations induced by currents and waves Ship motions on vicinity of a structure Minimisation of vertical motions of floating structures Prediction of slow drift oscillations of a moored ship in head seas Fundamental considerations for cyclic triaxial tests on saturated sand Some aspects of sand liquefaction under cyclic loading Behaviour of clay subjected to undrained cyclic loading

Water fuel emulsion is widely used to control pollutant emissions in large and medium diesel engines. The application of this fuel to small automotive engines has been limited by the emulsion stability and economic difficulties to calibrate engine parameters for a new fuel. The focus here is on the effects of the use of water fuel emulsion on standard automotive engines' performances and on pollutant emissions. After a brief description of the diesel particulates-sampling device the diesel test engines used and the pollutant analysis apparatus the effect of water-fuel combustion and engine parameters (air-fuel ratio and BMEP (break mean effective pressure)) on regulated pollutants (CO HC NOx and CO2) are summarised. Finally their effects on diesel particulates composition (PAH SOF) for several engine parameters and cold start is presented.

GCH (gas-cemented hardground) has previously been described from the Norwegian Continental Shelf but it was thought to be only of local lateral extent. The phenomenon is encountered at very shallow depths below seabed and is hence a potential hazard to seabed engineering work. During the installation of the Enicom North fibre optic cable in the Norwegian Sector of the North Sea in 2001 GCH was extensively encountered. Considerable problems were experienced during the trenching works with the hardground having significant impact on both the speed of burial operations and the depth of burial achieved. Post-lay ROV video records of many kilometres of trench were examined. The generally excellent quality images provide a comprehensive and detailed visual database that reveals a variety of hardground development stages and forms the basis for this paper. The presence and degree of GCH can be correlated with the trenching performance and an assessment made of its impact on the installation works. Conclusions and recommendations are presented.

An experiment on the stability of a ro-ro passenger ship with side damage is conducted in beam seas. Capsize only occurs with small GM values which does not satisfy SOLAS regulations. In non-capsize conditions the ship keeps a stationary condition with constant mean values of ha (heel angle) and water volume on deck. The effect of experimental parameters on these values and the capsize conditions are discussed. The effect of resonance of roll motion is also investigated. The mean height of water on deck above the calm sea surface which almost has a certain positive value in various conditions is proposed as an index for the stationary condition. It is concluded that the possibility of capsize can be evaluated without knowing the exact value of Hd using an equilibrium curve that is calculated and plotted on an Hd-ha diagram.

SSF (solar stimulated fluorescence) signals have been identified as a diagnostic identifier for phytoplankton populations and efforts are underway to relate these signals to algal physiology. However in coastal waters one must also take into account the effect of algal and non-algal materials on the underwater light field as this could have an impact on fluorescence excitation and propagation to the sea surface. The impact of varying loads of mineral particles and CDOM (coloured dissolved organic materials) on water-leaving SSF signals is examined using hydrolight radiative transfer simulations. The impact of algal and non-algal absorption and scattering on the production and propagation of SSF signals is assessed using realistic ranges of material concentrations and specific IOPs (inherent optical properties) derived from in situ data. It is shown that SSF signals in coastal waters are profoundly dependent on underwater light climates that are in turn strongly influenced by non-algal materials.

A podded propulsion system is a unit in which either a motor to drive the propeller is placed inside the pod or alternatively mechanically geared with motor outside the pod. A set of experiments has been designed to measure the contact ice loads on a model podded propulsion system. The objective of these tests is to determine a relationship between the ice thickness in which a vessel navigates and the resulting cyclic loading experienced by the pod stern bearing and propeller. This relationship would then be used to modify existing shipping regulations pertaining to the machinery design for arctic conditions. The paper describes the experimental setup and presents some of the results obtained. The experimental system is designed and built to measure the loads on the blade on the propeller shaft bearings on the shaft and on the whole propulsion unit (global loads).

The effect of different insulation scenarios on the transient characteristic of oil-gas-water multiphase flow in deepwater catenary risers is investigated. A systematic study of risers with the pipe-in-pipe configurations and different insulation materials and with an external insulation material is presented. The impact of insulation techniques on multiphase up-flow crude in the riser is clarified and the phenomena based on the fundamentals of multiphase flow and heat transfer is discussed. Numerical transient analyses are conducted to simulate the system shut-in conditions. The effects of insulation scenarios on the temperature pressure and liquid holdup responses during the system cool down conditions are investigated. The results of this study enhance the understanding of multiphase flow transient behaviour in insulated deepwater pipeline-riser systems. Data tables graphs and diagrams appear on pages 6 to 10.

This paper concerns a detailed large-scale experimental study of wave loading on offshore platform decks. A series of model tests with wave loading on different types of deck elements has been performed in the large wave channel (GWK) at Forschungszentrum Kuste in Hannover Germany. During the tests the following parameters have been measured: wave elevations deck element inundation's wave kinematics profile and wave forces on the individual deck elements. The model test results are analysed to provide hydrodynamic load coefficients to a wave-in-deck load programme based on the concept of change of fluid momentum. The results will also be used to verify a CFD code based on the Volume of Fluid method.