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A modern digital seismic network, with many stations optimally distributed on the earthquake causative seismic zone, enables detection of very low magnitude earthquakes and determination of their source parameters. It is essential to associate to such kind of networks procedures to analyze the huge amount of continuously recorded data for monitoring the space-time-magnitude evolution of natural and/or induced seismicity. Hence, the demand for near-real-time, automated data collection and analysis procedures for assisting seismic network operators in carrying out microearthquake monitoring is growing. In response to this need, we designed a computational software platform, TREMOR, for fast and reliable detection and characterization of seismicity recorded by a dense local seismic network. TREMOR integrates different open-source seismological algorithms for earthquake signal detection, location, and source characterizations in a fully automatic workflow. We applied the platform in play-back mode to the continuous waveform data recorded during 1 month at the Japanese Hi-net seismic network in the Nagano region (Japan) and compared the resulting catalog with the Japan Meteorological Agency bulletin in terms of number of detections, location pattern and magnitudes. The results show that the completeness magnitude of the new seismic catalog decreased by 0.35 units of the local magnitude scale and consequently the number of events increased by about 60% with respect to the available catalog. Moreover, the fault plane solutions resulted coherent with the stress regime of the region, and the Vp/Vs ratio well delineated the main structural features of the area. According to our results, TREMOR has shown to be a valid tool for investigating and studying earthquakes, especially to identify and monitor natural or induced micro-seismicity.

The hydrodynamics of a ship in prescribed motionis addressed by unsteady simulations using a hybridRANS/BEM solver. The interactive methodology com-bines a viscous-flow model addressing the flow aroundthe ship with a potential-flow model describing the loadsinduced by the vorticity generated at the propeller. Animplicit iterative procedure is provided in the time cy-cle through a body-force/effective inflow approach. Thepresent model is validated through comparisons about thevelocity flow-field and blade loads of numerical predictionsand measurements collected during an experimental cam-paign of a ship model in calm water moving in straightahead and steady drift motion. In particular, the nomi-nal tridimensional flow at the propeller disc is providedby the application of a stereo PIV technique, based on theuse of boroscopic equipment, whereas the transient singleblade loads are collected using a novel set-up adopting a 6-component multi-axial force transducer constrained at theroot blade itself. In spite of the inability of the model to ac-count for the blade boundary layer, the flow-field descrip-tion is detailed enough outside the propeller region whileassuring a limited computational burden related to meshgeneration. The present methodology represents a viablesolution to address the flow of maneouvring ships.

This paper describes U-SWATH an innovative Unmanned Surface Vehicle (USV), based on a Small Waterplane Area Twin Hulls (SWATH) design, developed by CNR INSEAN and ISSIA for institutional research purposes. The vehicles is composed of a wide flat deck covered with solar panels which connects two torpedo hulls. The hulls are composed of modular and interchangeable sections that can be outfitted with different payloads, equipments, propulsive or manoeuvring elements. The propulsion system is based on ad hoc electrical azimuthal thrusters. The solar panels covering the wide U-SWATH bridge are used for recharging the batteries supplying power to the vehicle. U-SWATH is multitasking and the goal of the designers was to develop a cutting-edge autonomous multi-purpose platform for carrying out research in the marine and the maritime fields.

A generalised hybrid RANSE/BEM model for the analysis of hull/propeller interaction in ship hydrodynamics problems at reduced computational cost is presented. Akin to standard hybrid RANSE/BEM models, the coupling between viscous and inviscid- flow solvers is based on a volume-force/effective-inflow approach. The generalization con- sists in coupling a time-accurate solution by BEM of the unsteady flow around the rotating propeller with the solution of the surrounding viscous-flow by unsteady RANSE to account for transient-flow propeller perturbation. The methodology is validated through numeri- cal applications to a simple case study describing a propeller in uniform flow conditions. Numerical results by the proposed hybrid RANSE/BEM model are compared with results by full-RANSE simulations and the capability of the methodology to correctly describe transient propeller flow perturbation to a surrounding viscous flow is investigated.

This technical report concerns with numerical investigations carried-out at the CNR-INSEAN CFD laboratories on Ducted Vertical Axis Tidal Turbine. Scope of the activities is the definition of a basic ducted turbine configuration, by the numerical analysis of different configurations, related to basic ducted geometry quantities and operative condition. The activity is performed using both viscous flow models and quasi steady flow models. The work consists first on the definition of a baseline duct configuration through a parametric numerical analysis; then, an isolated turbine model is applied to predict unsteady loads of the device in operative conditions. Data analysis provides basic information with respect to the global power extraction rate of the device investigated, whereas highlights the opportunity to develop numerical models to enhance the accuracy of results. This document represents the Project Deliverable 3.0 in fulfillment to tasks 1 - 3 of Contract 05CT12.

In the present paper, a computationally efficient methodology to develop fast and reliable propeller selection procedures based on a fully automated optimization technique is described. To this aim, a comprehensive propeller hydrodynamics model is combined with performance prediction acceleration techniques based on Neural Networks. Under given operating conditions, screw characteristics and blade shape details are optimized around a baseline configuration via general-purpose numerical optimization software based on genetic algorithms and via a parametric model. Numerical applications concern the propulsion retrofitting of marine vessels. A off-design performance verification study is presented to evaluate the robustness of the identified optimal configurations.

An automated computational methodology for the preliminary design of marine propellers is presented. A neural network architecture is developed to describe the performance of propeller models from a virtually-generated systematic series. Propeller performance predictions are based on a propeller hydrodynamics model based on a inviscid-flow model. Next, propeller geometry optimization is investigated through a Genetic Algorithm formulation. The structure of the resulting propeller design environment is illustrated and Neural Network, optimization models are validated through comparisons with existing experimental data and results from alternative approaches. Numerical applicatuions to a notional dessign exercise addressing a propeller retrofit study for an aged fishing vessel are also presented.

A theoretical and computational methodology to study marine propeller flows inside a closed tunnel is presented. The hydrodynamic model is based on a boundary integral formulation for the velocity potential that is valid for inviscid irrotational flows. The flowfield around a rotating propeller inside the tunnel is studied by a transient flow analysis in which both propeller and tunnel walls are simultaneously taken into account. An efficient numerical solution procedure is proposed by introducing a domain decomposition technique and a Fourier series representation of the influence coefficients. An outline of the theoretical methodology and of the numerical solution approach is described in the paper. Numerical scheme performance is discussed in detail and preliminary numerical results are presented. In particular, the evaluation of flow confinement effects for tunnel test sections of arbitrary shape and dimensions is discussed. It is also shown that the proposed methodology allows to predict tunnel velocity corrections based on the thrust identity approach, and numerical results are compared to those by classical analytical theory.