CNR Italian Ship Model Basin

www.insean.cnr.it/
Rome, Italy

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Grant
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: SST.2008.1.1.8. | Award Amount: 10.91M | Year: 2010

Increasing environmental concerns and soaring oil prices are creating a new focus on fuel efficiency for the marine industry. Combining low emissions with demands for more advanced vessels than ever before drives the need for radically new propulsion concepts delivering a step-change in efficiency. STREAMLINE is the response of the marine community to this demand that will be addressed through four key objectives. The first objective of STREAMLINE is to demonstrate radically new propulsion concepts delivering an increase in efficiency of at least 15% over current state-of-the-art. The concepts will be designed for maximisation of energy conversion combined with low levels of cavitation, noise and vibration. The research will look at novel applications of large area propulsion, a biomechanical system and distributed thrust (via multiple propulsors). As its second objective, STREAMLINE will investigate methods to fully optimise current SoA systems including conventional screw propeller systems, pods and waterjets. The key here is exploitation of new CFD methods to pursue improvements without dramatic vessel configuration changes. The third objective of STREAMLINE is to develop advanced CFD tools and methods to optimise the hydrodynamic performance of the new propulsion concepts, particularly by analysis of integrated hull and propulsor. Finally, STREAMLINE will characterise the operational, economic and classification aspects of each of the new propulsion concepts. STREAMLINE will demonstrate solutions for a wide range of applications. Short sea shipping and inland waterway operation will be focussed on specifically, as they are identified as key components of transport that can provide a means of coping with the growing congestion of road and rail infrastructure and tackling air pollution. The STREAMLINE consortium, led by Rolls-Royce, is made up of 30 partners from 8 Countries, providing world leading expertise and capability from the EU marine Industry.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: SST.2008.1.1.3. | Award Amount: 5.08M | Year: 2009

Transports are well known to be major contributors to noise pollution. Noise and vibrations (N&V) abatement naturally appears as an important objective for in the greening of surface transports. The SILENV project is a response to this requirement for the maritime domain. The consequences of N&V emissions from the ships are multiple. N&V emissions constitute a disturbance for both passengers and harbour area residents, and in some cases it may be a health issue for crew members. Moreover, the increasing ship traffic-generated underwater noise causes ecological nuisances on marine wildlife. This project proposes a holistic approach to reduce ship-generated Noise & Vibration pollution. After a definition of realistic target levels, existing experimental data from main types of ships and on-site measurements will be analysed to identify the most critical sources of noise and vibration. Innovative solutions will be listed and individually assessed on technical and economical criteria. These solutions shall subsequently be virtually tested and refined on numerical models of entire ships, thus allowing us to scientifically grade N&V improvements. SILENV final main deliverable is a green label proposal that includes recommended target levels for N&V and associated design guidelines.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: AAT.2010.3.3-1.;AAT.2010.4.1-1. | Award Amount: 5.73M | Year: 2011

Ditching analysis is requested for large transport aircraft by EASA. The respective requirements are specified under CS 25.801 Ditching. They are primarily devoted to a minimisation of risks for immediate injuries and the provision of fair chances for an evacuation. A significant part of average air travel is over water and historically a planned or unplanned water-landing event occurs grossly speaking every 5 years. This proposal directly addresses areas 7.1.3.3: Aircraft Safety and 7.1.4.1: Aircraft Development Cost. The primary outcome of the SMAES project will be advanced methodologies and simulation tools to support aircraft development from pre-project phase to certification. These will enhance future innovation in aircraft design through ensuring that innovative designs are compliant with safety requirements The key developments addressed in the work programme are: 1. Improved models for the calculation of ditching loads including both analytical and detailed fluid dynamics models. Inclusion of the effects of the complex flow physics in ditching is critical to prediction of ditching loads. 2. Reliable and predictive aircraft models for structural behaviour under dynamic fluid loads. 3. Demonstration of the methods on representative future aircraft design concepts. The consortium brings together aircraft manufacturers, analysis software developers, research organisations and universities. Together the partners form a strong team covering the required expertise in aircraft design, numerical methods and simulation, ditching analysis and supporting experimental methods to achieve the project objectives.


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ICT-2007.8.0 | Award Amount: 2.49M | Year: 2009

The objective of NextMuSE is to initiate a paradigm shift in the technology of Computational Fluid Dynamics (CFD) and Computational Multi-Mechanics (CMM) simulation software which is used to model physical processes in research and technology development across a range of industries. NextMuSE relies on a mesh-free method, Smoothed Particle Hydrodynamics (SPH), which is fundamentally different from conventional techniques and can overcome their shortcomings. The NextMuSE paradigm is defined by two characteristics: - accurate robust multi-mechanics modelling in applications where traditional methods fail (e.g. simultaneous fluid and solid mechanics in a ship under extreme wave loading). - an immersive, interactive user interface (ICARUS) to allow the user-engineer to manage and partially automate the extremely complex inputs and outputs of such multi-mechanics simulations. The objectives will be achieved through 7 work packages. 1: Key enhancements of core SPH algorithms. 2: Adapted physical modelling of fluids: turbulence, multiphase flow. 3: Modelling of fluid-structure interaction. 4: High-performance computing: highly efficient scalable algorithms for very large simulations. 5: Development of an immersive and highly visual simulation/design environment to interact with the technology. 6: Realistic representative applications in the marine, energy and biomedical industries. 7: Dissemination, communication and exploitation. This project will remove technology roadblocks and enable an enhanced and extended role for ICT and HPC in socio-economically important engineering RTD and innovation sectors (including energy, healthcare and transport). Although there are challenging scientific bottlenecks, risk is managed and minimised through the design of the work plan and the selection of the consortium. The risk is balanced by the potential reward for this project, which is a proof-of-concept for a paradigm shift which will open the way for advanced immersive HPC simulation tools, seamlessly integrated into the RTD process for the most challenging engineering problems.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: SST.2008.1.1.2. | Award Amount: 3.03M | Year: 2009

Marine diesel electric and hybrid drive systems have been used in large ships and submarines for many years but have not yet been successfully transferred to smaller craft, despite claims to the contrary. Numerous attempts have been made, some very recent, but all have been sub optimal and most have failed completely. These failures are due to a lack of underpinning research and of certain key components. The project has the following objectives: Zero emissions to air and zero external noise and vibration in port Reduction of overall fuel consumption by 30%, tending to >90% on applications such as long distance sailing boats using regenerative techniques CO2 reduction of >30% in all off design point applications (e.g.fishing boats and small commercial ferries) 50% reduction in HC & NOx The market for small hybrid drive systems is tens of thousands of units and the aggregate social and environmental benefits are substantial. A holistic approach will be taken to total energy consumption and production on board. At the centre of the new system will be a comprehensive energy management module which will supervise and control energy flows in and out of a specially designed battery bank. The NMEA 2000 standard will be developed as necessary for the new data formats. Safety issues will be addressed by developing new ISO standards. The following research, development and validation will be carried out: High efficiency, low speed, torque following propeller Rim drive propulsor using an embedded permanent magnet DC (PMDC) motor and contra rotating blades Load following, dynamic PMDC motor and generator controllers High efficiency DC to DC converters High efficiency AC to high voltage DC multi output battery charger Control algorithms for key components The final deliverables will be a validated hybrid drive system for small craft, a design tool, critical new components including a new propeller, and contributions to NMEA and ISO standards.


Marino E.,University of Florence | Lugni C.,CNR Italian Ship Model Basin | Borri C.,University of Florence
Computer Methods in Applied Mechanics and Engineering | Year: 2013

We present a novel numerical procedure for the prediction of nonlinear hydrodynamic loads exerted on offshore wind turbines exposed to severe weather conditions. The main feature of the proposed procedure is the computational efficiency, which makes the numerical package suitable for design purposes when a large number of simulations are typically necessary. The small computational effort is due to (i) the use of a domain-decomposition strategy, that, according to the local wave steepness, requires the numerical solution of the nonlinear governing equations only on a limited number of reduced regions (sub-domains) of the whole space-time domain, (ii) the choice of the particular numerical method for the spatial discretization of the governing equation for the water-wave problem. Within the potential flow assumption, the Laplace equation is solved by means of a higher-order boundary-element method (HOBEM). For the time evolution of the unsteady free-surface equations the 4th-order Runge-Kutta algorithm is adopted. The compound solver is successfully applied to simulate nonlinear waves up to overturning plunging breakers, that may cause severe impact loads on the wind turbine substructure.Emphasis is finally given to wind turbine exposed to realistic environmental conditions, where the proposed tool is shown to be capable of capturing important nonlinear effects not detected by the linear models routinely adopted in the design practice. © 2012 Elsevier B.V.


Iafrati A.,CNR Italian Ship Model Basin
Journal of Geophysical Research: Oceans | Year: 2011

The breaking of free surface waves is investigated numerically via a Navier-Stokes model for the two-fluids flow of air and water. Third order Stokes waves in a periodic domain are simulated. The fundamental wavelength is 27 cm, whereas the initial steepness varies from low values, leading to regular wave trains, up to artificially steep wave trains yielding plunging breaking events. Attention is focused on the early stage of the breaking, when most of the energy is dissipated. The energy content in air, the fraction associated to surface tension effects, the viscous dissipation in water, and the work done against the pressure field are analyzed in order to distinguish the different contributions to the dissipation. Vorticity fields and dissipation contours are also presented. In the spilling case, the extra energy content with respect to the steepest nonbreaking case focusses into the breaking region and is gradually dissipated. Once the extra energy has been dissipated, the resulting wave matches the steepest nonbreaking solution. In the plunging case, an important role is played by the air entrainment. A fraction between 10 to 35% of the energy dissipated by the breaking is spent in entraining the air cavity, and most of it is dissipated by viscous effects when the cavity collapses. The phenomenon is clearly highlighted by sequences of vorticity and dissipation contours. The circulation and the area of the cavity generated by the plunging of the jet are provided, and parametric dependencies are proposed. Copyright 2011 by the American Geophysical Union.


Ianniello S.,CNR Italian Ship Model Basin
21st International Congress on Sound and Vibration 2014, ICSV 2014 | Year: 2014

This paper aims to numerically demonstrate that the underwater noise generated by a marine propeller is an essentially nonlinear problem and that, unlike the analogous aeronautical configurations, the nonlinear flow noise sources play a dominant role independently of the low rotational speed of the blade. To this aim the prediction of the thickness noise component only (in air) is carried out on two typical blade models corresponding to a helicopter rotor and a marine propeller, in order to assess how the main structural and geometrical differences between these two bodies (the aspect ratio, the twist and thickness distribution along span) can affect the resulting noise in the far field.


OFF, an open source (free software) code for performing fluid dynamics simulations, is presented. The aim of OFF is to solve, numerically, the unsteady (and steady) compressible Navier-Stokes equations of fluid dynamics by means of finite volume techniques: the research background is mainly focused on high-order (WENO) schemes for multi-fluids, multi-phase flows over complex geometries. To this purpose a highly modular, object-oriented application program interface (API) has been developed. In particular, the concepts of data encapsulation and inheritance available within Fortran language (from standard 2003) have been stressed in order to represent each fluid dynamics "entity" (e.g. the conservative variables of a finite volume, its geometry, etc...) by a single object so that a large variety of computational libraries can be easily (and efficiently) developed upon these objects. The main features of OFF can be summarized as follows: Programming LanguageOFF is written in standard (compliant) Fortran 2003; its design is highly modular in order to enhance simplicity of use and maintenance without compromising the efficiency; Parallel Frameworks Supported the development of OFF has been also targeted to maximize the computational efficiency: the code is designed to run on shared-memory multi-cores workstations and distributed-memory clusters of shared-memory nodes (supercomputers); the code's parallelization is based on Open Multiprocessing (OpenMP) and Message Passing Interface (MPI) paradigms; Usability, Maintenance and Enhancement in order to improve the usability, maintenance and enhancement of the code also the documentation has been carefully taken into account; the documentation is built upon comprehensive comments placed directly into the source files (no external documentation files needed): these comments are parsed by means of doxygen free software producing high quality html and latex documentation pages; the distributed versioning system referred as git has been adopted in order to facilitate the collaborative maintenance and improvement of the code; CopyrightsOFF is a free software that anyone can use, copy, distribute, study, change and improve under the GNU Public License version 3. The present paper is a manifesto of OFF code and presents the currently implemented features and ongoing developments. This work is focused on the computational techniques adopted and a detailed description of the main API characteristics is reported. OFF capabilities are demonstrated by means of one and two dimensional examples and a three dimensional real application.


Mariani R.,CNR Italian Ship Model Basin | Dessi D.,CNR Italian Ship Model Basin
Journal of Fluids and Structures | Year: 2012

In this paper a time-domain procedure to identify the vibration modes of floating structures, based on the analysis of both displacements and accelerations, is presented. The implemented time-domain technique is the proper orthogonal decomposition (POD), known also as Karhunen-Loeve decomposition, that provides the functional basis that accounts for more captured energy than any other orthogonal one. The POD has been applied in its straightforward formulation and in a slightly different version as well, named band-pass POD, that exploits preliminary filtering around the resonant peaks of the analyzed signals to enhance the convergence of the proper orthogonal modes (POMs) to the linear normal modes (LNMs) in the case of poor information about the mass distribution. The presented procedure has been employed to analyze the experimental data provided by accelerometers and strain-gages applied to the flexible backbone of an elastically scaled segmented-hull model tested in both irregular sea and regular waves in the towing-tank. Among several aspects of the identification of wet-modes, it is discussed in particular how the excitation mechanism provided by the sea meets the requirements of the ambient load typically exploited in output-only modal analysis. The comparisons between the mode shapes identified with the two different procedures (classical POD on the displacements and band-pass POD on the accelerations) show the effectiveness of the POD and the possibilities and limitations related to the use of each procedure. Some results related to the present application, like energy ordering of the wet-modes and its dependence on the encountered sea pattern, as well as the modal damping variation with ship forward speed, are discussed in the paper, showing the POD capability to provide new insights in the analysis of hydroelastic phenomena. © 2011 Elsevier Ltd.

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