7 research outputs found

    Contravariant Boussinesq equations for the simulation of wave transformation, breaking and run-up

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    We propose an integral form of the fully non-linear Boussinesq equations in contravariant formulation, in which Christoffel symbols are avoided, in order to simulate wave transformation phenomena, wave breaking and near shore currents in computational domains representing the complex morphology of real coastal regions. The motion equations retain the term related to the approximation to the second order of the vertical vorticity. A new Upwind Weighted Essentially Non-Oscillatory scheme for the solution of the fully non- linear Boussinesq equations on generalised curvilinear coordinate systems is proposed. The equations are rearranged in order to solve them by a high resolution hybrid finite volume–finite difference scheme. The conservative part of the above-mentioned equations, consisting of the convective terms and the terms related to the free surface elevation, is discretised by a high-order shock- capturing finite volume scheme; dispersive terms and the term related to the approximation to the second order of the vertical vorticity are discretised by a cell-centred finite difference scheme. The shock-capturing method makes it possible to intrinsically model the wave breaking, therefore no additional terms are needed to take into account the breaking related energy dissipation in the surf zone. The model is applied on a real case regarding the simulation of wave fields and nearshore currents in the coastal region opposite Pescara harbour (Italy)

    Modeling bed evolution using weakly coupled phase-resolving wave model and wave-averaged sediment transport model

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    In this paper, we propose a model for the simulation of the bed evolution dynamics in coastal regions characterized by articulated morphologies. An integral form of the fully nonlinear Boussinesq equations in contravariant formulation, in which Christoffel symbols are absent, is proposed in order to simulate hydrodynamic fields from deep water up to just seaward of the surf zones. Breaking wave propagation in the surf zone is simulated by integrating the nonlinear shallow water equations with a high-order shock-capturing scheme. The near-bed instantaneous flow velocity and the intra-wave hydrodynamic quantities are calculated by the momentum equation integrated over the turbulent boundary layer. The bed evolution dynamics is calculated starting from the contravariant formulation of the advection-diffusion equation for the suspended sediment concentration in which the advective sediment transport terms are formulated according to a quasi-three-dimensional approach, and taking into account the contribution given by the spatial variation of the bed load transport. The model is validated against several tests by comparing numerical results with experimental data. The ability of the proposed model to represent the sediment transport phenomena in a morphologically articulated coastal region is verified by numerically simulating the long-term bed evolution in the coastal region opposite Pescara harbor (in Italy) and comparing numerical results with the field data

    A model for the simulation of the bed evolution dynamics in coastal regions characterized by articulated morphologies

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    This thesis presents the research project completed during the Ph.D. course in Environmental and Hydraulic Engineering at Sapienza University of Rome. The main element of novelty in the above research project is related to the capability of the proposed model to represent sediment transport phenomena that affect long-term bed evolution dynamics in morphologically articulated coastal regions. The proposed model for the simulation of the bed evolution dynamics consist of two parts: a two-dimensional phase-resolving model for the simulation of the hydrodynamic fields and a morphodynamic model based on the advection-diffusion equation for the suspended sediment concentration. In this model the governing equations are written in an integral contravariant formulation in order to permit the numerical integration of the above-mentioned equations on generalized curvilinear grids representing real coastal regions characterized by articulated morphologies. An integral form of the fully non-linear Boussinesq equations in contravariant formulation, in which Christoffel symbols are absent, is proposed in order to simulate hydrodynamic fields from deep water up to just seaward of the surf zones. Breaking wave propagation in the surf zone is simulated by integrating the non-linear shallow water equations with a high-order shock-capturing scheme: an exact Riemann solver and a weighted essentially non-oscillatory reconstruction technique are used. In order to take into account the sediment transport in the swash zone a new procedure for the simulation of the uprush and backwash dynamics of the wet and dry front is proposed. The near-bed instantaneous flow velocity, the instantaneous wave boundary layer thickness, the friction velocity and the bed shear stress (which are involved in the sediment particle resuspension and settling processes) are calculated by the momentum equation integrated over the turbulent boundary layer. The bed evolution dynamics is calculated starting from the contravariant formulation of the advection-diffusion equation for the suspended sediment concentration. The advective sediment transport terms that appear in the above-mentioned equation are formulated according to a quasi-three dimensional approach and are calculated starting from the depth integration of the product of the horizontal velocity vertical distribution and suspended sediment concentration vertical distribution, in order to take into account the sediment transport related to the undertow. The net sediment transport rate from the swash zone in the cross-shore direction, evaluated starting from the hydrodynamic quantities produced by the wet and dry front dynamics simulation, is used as a boundary condition of the above-mentioned equation. The computing of the long-term bed evolution dynamics is carried out by a sequence that alternates, at each step (morphological step), the simulation of wave and current velocity fields and the simulation of the sediment transport and bed morphological change. The model is validated against several tests by comparing numerical results with experimental data. The ability of the proposed model to represent the sediment transport phenomena in a morphologically articulated coastal region is verified by numerically simulating the long-term bed evolution in the coastal region opposite Pescara harbor (in Italy) and comparing numerical results with the field data. Furthermore in the same coastal region, the model has been also applied to study the long-term effects produced by the presence of a designed submerged breakwater on the bed evolution dynamics.Most of the results reported in this thesis are part of a scientific paper submitted on the international journal Coastal Engineering - Elsevier: “A model for the simulation of the bed evolution dynamics in coastal regions characterized by articulated morphologies”, Gallerano F., Cannata G., De Gaudenzi O., Scarpone S., 2015

    Energy harvesting applications in transportation infrastructure networks

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    In the upward trend of renewable energy growth, several proposals have been made concerning energy harvesting devices in transportation infrastructure networks. The objective, concerning higher power extraction, is to supply power to auxiliary systems (e.g. road lights or information panels), thus, satisfying the requirement for sustainable transportation infrastructures. The purpose of this paper is to define a broader framework of energy extraction for transportation infrastructure networks. Within this framework, a novel device for the vibration energy harvesting, based on piezoelectric material, is modeled in a commercial FEM (Finite Element Method) code, in order to optimally extract energy from wind-induced vibrations. (C) 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility of the Programme Committee of he Transport Research Arena 201

    A new numerical model for simulation of wave transformation, breaking and run-up in complex coastal regions

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    We propose an integral form of the fully non-linear Boussinesq equations in contravariant formulation, in which Christoffel symbols are avoided, in order to simulate wave transformation phenomena, wave breaking and near shore currents in computational domains representing the complex morphology of real coastal regions. Following the approach proposed by Chen (2006), the motion equations retain the term related to the approximation to the second order of the vertical vorticity. A new Upwind Weighted Essentially Non-Oscillatory scheme for the solution of the fully non-linear Boussinesq equations on generalised curvilinear coordinate systems is proposed. The equations are rearranged in order to solve them by a high resolution hybrid finite volume–finite difference scheme. The conservative part of the above- mentioned equations, consisting of the convective terms and the terms related to the free surface elevation, is discretised by a high-order shock-capturing finite volume scheme; dispersive terms and the term related to the approximation to the second order of the vertical vorticity are discretised by a cell-centred finite difference scheme. The shock-capturing method makes it possible to intrinsically model the wave breaking, therefore no additional terms are needed to take into account the breaking related energy dissipation in the surf zone. The model is verified against several benchmark tests, and the results are compared with experimental, theoretical and alternative numerical solutions

    The management of acute venous thromboembolism in clinical practice - study rationale and protocol of the European PREFER in VTE Registry

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    Background: Venous thromboembolism (VTE) is a major health problem, with over one million events every year in Europe. However, there is a paucity of data on the current management in real life, including factors influencing treatment pathways, patient satisfaction, quality of life (QoL), and utilization of health care resources and the corresponding costs. The PREFER in VTE registry has been designed to address this and to understand medical care and needs as well as potential gaps for improvement. Methods/design: The PREFER in VTE registry was a prospective, observational, multicenter study conducted in seven European countries including Austria, France Germany, Italy, Spain, Switzerland, and the UK to assess the characteristics and the management of patients with VTE, the use of health care resources, and to provide data to estimate the costs for 12 months treatment following a first-time and/or recurrent VTE diagnosed in hospitals or specialized or primary care centers. In addition, existing anticoagulant treatment patterns, patient pathways, clinical outcomes, treatment satisfaction, and health related QoL were documented. The centers were chosen to reflect the care environment in which patients with VTE are managed in each of the participating countries. Patients were eligible to be enrolled into the registry if they were at least 18 years old, had a symptomatic, objectively confirmed first time or recurrent acute VTE defined as either distal or proximal deep vein thrombosis, pulmonary embolism or both. After the baseline visit at the time of the acute VTE event, further follow-up documentations occurred at 1, 3, 6 and 12 months. Follow-up data was collected by either routinely scheduled visits or by telephone calls. Results: Overall, 381 centers participated, which enrolled 3,545 patients during an observational period of 1 year. Conclusion: The PREFER in VTE registry will provide valuable insights into the characteristics of patients with VTE and their acute and mid-term management, as well as into drug utilization and the use of health care resources in acute first-time and/or recurrent VTE across Europe in clinical practice. Trial registration: Registered in DRKS register, ID number: DRKS0000479
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