1,721,073 research outputs found
Nuova unità di concezione multiscafo adibita al recupero degli idrocarburi sversati in mare
No full textLa preoccupante ricorrenza e la sempre maggiore gravità degli incidenti che originano sversamenti in mare di idrocarburi dimostrano la necessità di una continua evoluzione di mezzi e tecniche che
consentano di fronteggiare in modo rapido ed efficace il problema, senza produrre ulteriori effetti
collaterali sull’ecosistema marino.
La particolare unità multiscafo descritta nel presente articolo è dimensionata per poter alloggiare a
bordo un innovativo impianto di recupero del petrolio sversato accidentalmente in mare, che sfrutta le
ottime proprietà di assorbimento della lana non trattata (oleofilica e idrorepellente), conosciute fin
dall’antichità ma non ancora mai realmente sfruttate per applicazioni marine atte al disinquinamento
da idrocarburi. Nell’articolo è presentato lo studio di fattibilità del mezzo ideato, di cui si descrivono
le principali caratteristiche geometriche, il profilo operativo e i principali impianti di bordo, con particolare riguardo al sistema di recupero e stoccaggio degli idrocarburi
Waterjet Craft Propulsion: Study and Validation of Jet Performance Prediction Techniques
No full text
6 DOF simulation of maneuvering and propulsive performance of a waterjet propelled mega yacht
No full textIn the present paper the current status of the development of the DINAV manoeuvrability and propulsion simulator for planing boats is described. This topic, despite not being widely covered in literature, has shown in past years an increasing industrial interest due the higher demand for high quality systems in the leisure boat market, including also optimised control systems, which are important for boat performances and safety. In order to respond to these needs, a mathematical model able to represent the 6 degrees of freedom motions of a vessel and the working characteristics of the propulsion plant has been implemented. A first application, regarding ‘Leopard 34’ by Cantiere Navale Arno, a 34 meters yacht propelled by 3 Rolls-Royce Kamewa Waterjets, is presented. Simulations obtained from the model have been qualitatively compared with some data acquired during full scale trials, and an analysis of the influence of various parameters on the craft manoeuvrability has been carried out, underlining some important aspects which need further research efforts and experimental validation
Fuel cost savings and pollution reduction by alternative propulsion technologies for Italian fisheries
No full textA proper use of sea trials data for marine propulsion simulations
No full textSimulation in engineering plants design should be used as a powerful tool in order to
investigate several design options in different working conditions. From this point of
view, simulation techniques are powerful only if they are reliable. Numerical simulation
codes are generally based on algebraic and differential equations that are usually tested
at the design working point of the represented dynamical systems; instead the validity of
the models to represent off design conditions is generally not well documented, due to
lack of information. Therefore one of the most difficult tasks in simulation problems is
developing complete numerical models, able to represent the entire working area of the
considered system.
The availability of full-scale experimental data to test and update mathematical models
becomes essential for the simulation developer, which could be able to improve the
fidelity of the simulation models, for similar applications, on the base on proved
experience.
The paper is focused on the validation process of the propulsion simulation code for a
naval vessel, developed at Genoa University. The simulation code has been used by the
automation provider in order to design and test the real propulsion control system on
board. To validate and to improve the code simulation results have been compared with
sea trials data. Simulation output regarding some dynamic models, as for instance the
engine model, was very reliable in the working points near the design conditions,
generally at the high engine loads. On the contrary, as it was expected, the major
discrepancies occurred at the lower engine loads, in particular where the design
characteristics, necessary for the numerical model development, were assumed or
extrapolated because their knowledge was not yet available during the design phase. In
particular, the engine simulation setup, based on a proper analysis of sea trials data, is
briefly described in this paper, in order to underline the importance to plan a proper
campaign of specific measurements on board, to be used in marine simulation field
VR simulation for the propulsive performance analysis of high-speed yachts
No full textThe paper describes the main features of a marine propulsion simulator for high-speed yachts, developed using Real-Time (RT) simulation and Virtual Reality (VR) techniques. In the last years, several studies about the dynamic behaviour of marine propulsion systems have been carried out at Genoa University but in the present study the interaction among planing boat motions in six degrees of freedom, waterjet propulsion dynamics and control system are integrated in one complete mathematical model. The time domain simulator is developed by Matlab-Simulink® software and a 3-D graphics model has been created by using a Virtual Reality Editor, in order to represent the three dimensions viewing of the simulated boat in a marine virtual scenario.
Finally, a comparison between numerical simulation results and full scale trials data is shown in order to analyze the propulsion system influence on the manoeuvrability characteristics of a waterjet propelled yacht
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