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This paper presents proposals on the creation of a scientific and educational Internet/Extranet Portal which could help integrate the intellectual potential of production science and education in the marine industrial sphere. Virtual reality technology can provide a backbone for wide-discussion and testing of abstract ideas for a virtual ship design prior to implementation in extremely labour and material intensive production. New forms of computer-based professional education will allow improvement in the safety of navigation; help reduce the negative effects of the 'human factor' and the cost of mastering ship machinery. The portal is socially-oriented and can help overcome the lag of the scientific and educational environment behind the advanced development of science-intensive and high-technology machinery and equipment. An efficient system of both higher and professional education will allow preservation of centuries-old history industrial culture and huma resource in the historical centres of Europena shipbuilding.

A probabilistic local random yielding model has been developed in simulating the uniaxial stress-strain curve. A statistical model is proposed in the nonlinear finite element analysis for the plastic deformation based on the probabilistic distribution of the random yielding of local microelements. A revised generalized equation is formulated using the local random yielding model to simulate the stress versus strain curve for the uniaxial tension test. After the background and literature survey are given the local random yielding model is described. The yielding surface by LYRM incremental stress-strain relationship local random yielding surface and incremental force-displacement matrix are considered and the results are compared.

The nonlinear motion of a ro-ro type ship with water on deck in regular beam seas is described. Model experiments show that a flooded ship can exhibit nonlinear roll motion in waves of relatively moderate height. This nonlinear response is investigated using a mathematical model for coupled motion of roll and flooded water of a box-shaped ship in waves. The model includes not only static but also dynamic effects of flooded water. The Jacobean matrix of the model equations has a discontinuous property. The method is presented to determine bifurcation values for this type of system. An example of the bifurcation analysis shows that when a ship is flooded both small harmonic and large sub-harmonic motion can co-exist in a wide range of a parameter.

In this work return periods of various level values of significant wave height in the Gulf of Mexico are given. The predictions are based on a new method for nonstationary extreme-value calculations that have recently been published. This enhanced method exploits efficiently the nonstationary modeling of wind or wave time series and a new definition of return period using the MEan Number of Upcrossings of the level value x* (MENU method). The whole procedure is applied to long-term measurements of wave height in the Gulf of Mexico. Two kinds of data have been used: long-term time series of buoy measurements and satellite altimeter data. Measured time series are incomplete and a novel procedure for filling in of missing values is applied before proceeding with the extreme-value calculations. Results are compared with several variants of traditional methods giving more realistic estimates than the traditional predictions. This is in accordance with the results of other methods that take also into account the dependence structure of the examined time series.

Seminar held 10 - 11 May 1977 in Oslo, Norway. Papers are Cut throat competition or cooperation in the tanker business The future of American and Soviet Shipping American shipping policy The Soviet merchant marine - looking ahead The American energy situation and the Arab intentions in the oil transport United States energy policy under President Carter Arab intention in oil transport and future developments Deep ocean mining and the prospects for bulk shipping Changes in international finance of shipping and ship building and related industries How can the Guarantee Institute assist ship owners - its influence on the shipowners activities during and after the crisis The flags of convenience and their implications to world shipping Flags of convenience registration - effects in developing and industrialised countries European ship building - which direction Greek shipowning outlook Quality assurance in ships of tomorrow

Reliable and accurate real-time monitoring and control systems are needed on Royal Navy vessels to ensure that air quality is maintained for long-term effective crew performance. This requirement applies to all classes of submarine and closed-down vessels. Novel methods for analysing and controlling ambient air quality in enclosed underwater environments are being developed by the Defence Research Agency. Recent advances in real-time toxic gas and organic vapour detection methods are highlighted. Electro- chemical sensors currently offer the best option for submarines but future submarine atmosphere monitoring is likely to include several different types of sensing technology. Signal processing methods to correct for cross sensitivities and temperature effects will then play an important role. The techniques are aimed at providing low- cost solutions with the minimum of onboard and onshore interactions.

The book describes the basic nuclear power technologies and discusses the factors that have determined and will continue to determine the formation of nuclear policies in different parts of the world. Authoritative surveys provide insight into nuclear power development in Europe, the USA and Canada, Japan, India and the developing countries including the Eastern bloc. The following subjects are covered: radiation and its effects, nuclear safety, waste management and decommissioning. The book provides an introduction to the technical background in the first section, looking at the underlying physics of nuclear power, nuclear reactor types, the nuclear fuel cycle and nuclear energy for uses other than electricity generation. The overall situation and future prospects for nuclear power are reviewed in terms of its economic, environmental and strategic attractions and of the constraints on its introduction in many parts of the world.

A numerical and experimental investigation of the influence of a vertical bend on the upstream and downstream flow conditions in a pipe system is described. SOPHY-2 a code developed to simulate the time-dependent behaviour of two-phase flow with fairly high liquid loading in such pipe systems is used to simulate the transitional flow in a vertical bend. Also the Maximum Entropy Method (MEM) for flow regime identification is used in the experiments. Firstly the experimental set-up is looked at. Next the experimental results are given. Lastly simulations are discussed.

The irregular frequency phenomenon relating to the numerical prediction of hydrodynamic forces on free-surface-piercing floating bodies using transient free surface Green function method is discussed in this paper. Two kinds of boundary integral equations are investigated. To obtain the fluid velocity without the influence of the irregular frequency a new source distribution model with redefined interior problem and a numerical scheme for computing the source strength and fluid velocity are proposed. Numerical validations are performed for both two- and three-dimensional bodies it is shown that the presented method is very stable and accurate and it is very suitable for the linear and nonlinear hydrodynamic force calculation of offshore structures.

The rotordynamic behavior of a hydraulic turbine is influenced by fluid-rotor interactions at the turbine runner. In this paper computational fluid dynamics (CFDs) are used to numerically predict the torsional dynamic coefficients due to added polar inertia, damping, and stiffness of a Kaplan turbine runner. The simulations are carried out for three operating conditions, one at about 35% load, one at about 60% load (near best efficiency), and one at about 70% load. The runner rotational speed is perturbed with a sinusoidal function with different frequencies in order to estimate the coefficients of added polar inertia and damping. It is shown that the added coefficients are dependent of the load and the oscillation frequency of the runner. This affect the system’s eigenfrequencies and damping. The eigenfrequency is reduced with up to 65% compared to the eigenfrequency of the mechanical system without the fluid interaction. The contribution to the damping ratio varies between 30–80% depending on the load. Hence, it is important to consider these added coefficients while carrying out dynamic analysis of the mechanical system.

A numerical algorithm is proposed to simulate the one component velocity flow in complex conduits such as eccentric annulus in the presence of a static cuttings bed. The method is applicable to the use of the various rheological models of laminar and turbulent flows. This flow situation can arise during the drilling or cementing of oil and gas wells. Knowledge of the velocity distribution during flow is important to predict the pressure drop needed to gain a desired flow rate and to determine the rates of heat and mass transfer accompanying such flows. The turbulent viscosity term which is modelled by the Zero-Equation Method is considered as an addition to the Power-law or Yield-Power-law viscosity terms. The zero-equation model proposed here is based on the approach developed in Buleev's works. The proposed method is applicable for the eccentricity up to 1 and for any height of the cuttings bed up to the top of the drillpipe.

The analysis of the influence of the real bottom and coastline contours in shoreline OWC (oscillating water column) plants (compared to when a structure is placed on a horizontal bottom in the middle of the ocean) was established by means of results computed by a numerical code. The case of the Pico wave power plant local bathymetry and shoreline has been used as an example. The results presented also confirmed that AQUADYN-OWC is able to be applied to onshore OWC devices. Finally a comparison of numerical- and scale-test results concerning the radiation impulse response function showed a good qualitative agreement in the first two peaks and some deviation for larger arguments. This result suggests further validation with data measured at the Pico OWC wave power plant.

The air gap response and potential deck impact of ocean structures under waves is addressed. In this paper an analytical prediction of the air gap for floating offshore structures using direct Boundary Element Method (BEM) is presented. Firstly the direct boundary element method is reviewed. Secondly the boundary value problem of interaction between regular sea waves and a semi-submersible and air gap responses due to the motion of the platform and the local wave elevations is described. Then the direct boundary element method is applied to predict the air gap at different field points of ALBORZ semi-submersible drilling unit. In addition the results obtained from the direct BEM is compared with those obtained by the designers of the ALBORZ semi-submersible. To determine the influence of the structure's motions on the air gap the results for both fixed and free-floating structure cases are compared. Physical simulations using model are carried out in the future in order to compare the results of the experiments with predictions.

CFD simulations of crossflows around a 2D circular cylinder and the resulting vortex shedding from the cylinder are conducted in the present study. The capability of the CFD solver for vortex shedding simulation from a circular cylinder is validated in terms of the induced drag and lifting forces and associated Strouhal numbers computations. The validations are done for uniform horizontal fluid flows at various Reynolds numbers. Crossflows around the circular cylinder beneath a free surface are also simulated. The influence of the presence of the free surface on the vortex shedding due to the cylinder is discussed.

Investigating structural responses in a physical wave tank is state of the art but calculation of structural responses in extreme sea states is still a challenging task as the wave environment needs to be modelled precisely. In this paper focus is put upon the calculation of nonlinear wave propagation in numerical wave tanks (NWTs). The aim is the exact simulation of wave propagation in a wave tank in order to provide the basis for numerical investigations of wave/structure interaction. In this paper different methods for modelling nonlinear wave propagation are presented: numerical wave tank based on potential theory in combination with a Finite Element method numerical wave tank using RANSE codes and the combination of potential theory and RANSE codes. In general good agreement between experiments and numerical simulations is observed.

Detailed observations were made of slug flow in an upward to downward pipeline configuration with thirteen capacitance sensors. The results presented in this study are based on four typical tests which demonstrate the phenomena encountered in slug dissipation. In downward flow slug frequency decreases with different extent at different flow rates. There is a reduction of slug length after the turning over from upward to downward flow. However the slug tends to recover its stable length in further downstream development except for flow that quickly becomes stratified. Growth of the slug length is accomplished by picking up liquid left by the downstream dissipating slug before being fully absorbed by the liquid film.

Global Earth Observation systems have a unique capability and have already demonstrated significant applications towards understanding and managing the Earth's environment. Thanks to improved in situ networks spatial and temporal coverage of satellite remote sensing and numerical simulations operational oceanography is emerging to address major concerns (global monitoring disaster management support climate change issues etc). There are a vast number of challenges facing ocean remote sensing. Ultimate goals are to be able to make accurate estimates of selected key sets of geophysical variables with the intention of either making predictions across time and spatial boundaries or advancing fundamental knowledge through development of empirical relationships and-or theoretical models. Improvements are constantly being sought in both our understanding of the geophysical processes themselves the sensor physics and the electromagnetic and microwave properties of the surface and its associated air-sea interface as well as the sampling capabilities to ensure proper monitoring using the vast number of specialised technologies that can be selected to concentrate on one or a few of the physical processes for accurate measurements. The increasing quality quantity and duration of these ocean observations are then critically important for practical applications

This book presents stories of the recovery of sunken ships and deals with the technically complex craft of deep-sea salvage. Part One includes a short history of the subject, a description of the latest salvage methods and equipment, and some account of the techniques used to locate and mark a wreck on the ocean floor – a far trickier business than the layman might suppose. In Part Two the author describes eleven different typical operations in detail – including the Spanish Armada searches in Tobermory Bay, the raising of the scuttled German Fleet at Scapa Flow, the recovery of £2 million gold cargo from the Niagara in 1941, three deep-sea crashed aircraft recoveries (two British and one American), and two US naval submarine operations in mid-Atlantic (Thresher and Scorpion). Photos and sketches support the narratives as required, and each of these operations presents different points of absorbing technical interest.

A new floater concept based on proven technology but combining this technology in a novel way has been designed for Deepwater operation in the Gulf of Mexico and other deepwater locations. The Octabuoy SDM (Shallow Draught Mooring assisted) is a semi-submersible with a design and a tuned mooring system that ensure improved motion characteristics compared to other semi-submersibles. This makes the floater very well suited for accommodating Steel Catenary Risers (SCRs) in the Gulf of Mexico and dry tree solutions for West Africa. Motion results calculated for a typical Gulf of Mexico wave environment using a coupled time domain approach are confirmed by extensive model testing of the concept which proves the ability of the proposed concept to accommodate SCRs specifically for the Gulf of Mexico.

Single-carrier modulation and equalisation-based reception is currently considered to be the standard method to attain bandwidth-efficient transmission in underwater channels. However recently published experimental results showing practical OFDM communication in underwater channels at rates in the tens of kbits per second have generated much interest not only by the accomplishment itself but also because OFDM is an enabling technology that can be integrated with MIMO transmission to attain even greater transmission rates through spatial multiplexing. This work aims to contribute to a better understanding of the potential of OFDM by examining results from the UAB '07 experiment which was carried out in Trondheim fjord Norway. The proposed approach relies on passive time reversal for multi-channel combining of observed waveforms at an array of sensors prior to OFDM processing which produces an equivalent channel with a shorter impulse response that can be handled much more easily. A method is proposed for tracking the narrowband residual phase variations of the channel after Doppler pre-processing. This is a variation of an existing technique that can improve the spectral efficiency of OFDM by reducing the need for pilot symbols. Experimental results are presented and conclusions drawn.