59 research outputs found
Simulation of wave run-up by means of the exact solution of the wet/dry Riemann problem
An innovative method for the simulation of the hydrodynamics in the swash zone, related to the
wave run-up phenomenon, is presented. This method applies the exact solution of the Riemann problem over
a dry bed to correctly evaluate the celerity of water waves propagating over the shore, and so to precisely track
the coastline location. The simulations of velocity and wave fields outside the surf zone, inside the surf zone
and in the swash zone, are carried out by means of a numerical model which solves 3D motion equations
expressed in integral form, with a vertical coordinate that varies in time in order to follow the free surface
evolution. Several numerical validation tests are carried out, in order to verify the capability of the method to
track the coastline
Numerical simulation of the sea bottom modifications behind a T-head groin
In this paper, we simulate the sea bottom modifications produced by the presence of a T-head groin. We present a simulation model of sea bottom modifications composed of two sub-models: a two-dimensional phase-resolving model that simulate the variation of the fluid dynamic variables inside the wave; a second sub-model to simulate the sea bottom modifications, in which the suspended sediment concentration is calculated by the wave-averaged advection-diffusion equation. The fluid motion equation and the concentration equation are expressed in a new contravariant formulation. The velocity fields from deep water up to just seaward of the surf-zone are simulated by a new integral contravariant form of the Fully Nonlinear Boussinesq Equations. The new integral form of the proposed continuity equation does not contain the dispersive term. The Nonlinear Shallow Water Equations, expressed in an integral contravariant form, are solved in order to simulate the breaking wave propagation. The momentum equation, integrated over the turbulent boundary layer, is solved to calculate the near-bed instantaneous flow velocity and the intra-wave hydrodynamic quantities. Starting from the contravariant formulation of the advection–diffusion equation for the suspended sediment concentration, it is possible to calculate the sea bottom modification. The advective sediment transport terms in the advection-diffusion equation are formulated according to a quasi-three-dimensional approach
3D numerical simulation of the interaction between waves and a T-head groin structure
The aim of coastal structures for the defense from erosion is to modify the hydrodynamic fields that would naturally occur with the wave motion, to produce zones of sedimentation of solid material, and to combat the recession of the coastline. T-head groin-shaped structures are among the most adopted in coastal engineering. The assessment of the effectiveness of such structures requires hydrodynamic study of the interaction between wave motion and the structure. Hydrodynamic phenomena induced by the interaction between wave motion and T-head groin structures have three-dimensionality features. The aim of the paper is to propose a new three-dimensional numerical model for the simulation of the hydrodynamic fields induced by the interaction between wave fields and coastal structures. The proposed model is designed to represent complex morphologies as well as coastal structures inside the domain. The numerical scheme solves the three-dimensional Navier-Stokes equations in a contravariant formulation, on a time-dependent coordinate system, in which the vertical coordinate varies over time to follow the free-surface elevation. The main innovative element of the paper consists in the proposal of a new numerical scheme that makes it possible to simulate flows around structures with sharp-cornered geometries. The proposed numerical model is validated against a well-known experimental test-case consisting in a wave train approaching a beach (non-parallel with the wave front), with the presence of a T-head groin structure. A detailed comparison between numerical and experimental results is shown
Wave Fields and Nearshore Currents in the Coastal Region Opposite San Mauro Cilento (Italy)
In this paper in order to simulate nearshore currents in computational domains representing the
complex morphology of real coastal regions we use a model based on a contravariant integral form of the fully
nonlinear Boussinesq equations (FNBE). The contravariant integral form, in which Christoffel symbols are
absent, of the continuity equation does not contain the dispersive term. The Boussinesq equation system is
numerically solved by a hybrid finite volume-finite difference scheme. The wave breaking is represented by
discontinuities of the weak solution of the integral form of the nonlinear shallow water equations (NSWE). The
capacity of the proposed model to correctly simulate the wave train propagation on a highly distorted grid is
verified against test case present in the literature. The simulation of wave fields and nearshore currents in the
coastal region, opposite San Mauro Cilento (Italy) in presence of a system of T-head groins, is numerically
reproduced by using the proposed model
High-resolution morpho-bathymetry of the Gulf of Naples, Eastern Tyrrhenian Sea
ABSTRACTWe present a high-resolution bathymetric map of the Gulf of Naples (Italy), which is surrounded by the two main volcanic complexes of Mt. Somma-Vesuvius and Phlegrean Fields. The morphology is obtained from swath bathymetric in a Digital Terrain Model with a 5 m grid cell size. Bathymetric data display the main seafloor morphologies with a resolution never obtained before. These morphologies include the Ammontatura and Dohrn Canyons, the Penta Palummo, Nisida, Miseno and Banco della Montagna banks, and the bathymetric features of the submerged sector of the Somma-Vesuvius volcano. Overall, a prevailing volcanic nature characterizes the seafloor morphologies located in the northern sector, while the southern one is dominated by sedimentary features. The Final Map could be useful for the evaluation of the volcano-related hazards in the area
An Eddy-Current Testing Method for Measuring the Thickness of Metallic Plates
Thickness measurements of metallic plates are mandatory in many industrial scenarios. Methods based on eddy-current testing (ECT) are ideal for fast and accurate online contactless thickness measurements, making them very attractive in the Industry 4.0 scenario. This contribution is focused on a specific and robust ECT technique proposed in the past by the scientific community. The main limitation is its applicability to thin materials only, where the thickness of the material is much smaller than the overall size of the ECT probe. Extending the range of applicability to thicker materials introduces a progressive and severe degradation of the measurement accuracy. In this article, we analyze the theoretical foundation of this method with an entirely original approach based on the celebrated Buckingham π theorem. In doing this, we draw the complete theoretical picture of the method, providing a simple, clear, and rigorous view of its performance and intrinsic limitations. Moreover, we propose two solutions, one analytical and the other iterative, to accurately estimate the thickness of the materials from thin to thick values. Finally, a numerical analysis combined with an experimental campaign confirms the effectiveness of the proposed solutions, making the method suitable for industrial and other applications
A Digital Process for Manufacturing Customized Trays for Dental-Whitening Treatments
This study presents an alternative process for designing and manufacturing customized trays for dental-whitening treatments. The process is based on a digitized approach consisting of three main stages: design of a reference model, its manufacturing by AM, and thermoforming of the tray. The aim of the study was to develop a high-performance tray, able to guarantee comfort, safety, and efficacy for whitening treatments. To evaluate the patient’s experience, some tests under real operating conditions were performed. Twenty people carried out a nighttime treatment of 14 days. Each patient was asked to assess the overall level of satisfaction and the comfort of the tray and its ability to retain the gel. Tooth whitening was also determined according to the VITAPAN scale. All patients involved in the study were satisfied and provided positive feedback about comfort and tightness of the tray. At the end of the treatment, 15 out of 20 patients achieved shade A1 on the VITAPAN scale. The mean improvement in color shades was about 7. These results confirmed the great potential of the proposed dental tray. Its use was proven to guarantee a high level of quality, flexibility, and customization of dental-whitening treatments, improving comfort, safety, and efficacy
The Role of Hyaluronic Acid in Sport-Related Tendinopathies: A Narrative Review
Tendinopathy is a complex clinical condition with a rising incidence and prevalence, particularly during sports practice. For the return to play in affected patients, adequate functional and structural recovery of the tendon is the ultimate goal, avoiding the high risk of recurrence. In this perspective, local therapies alongside exercise are showing promising results. Despite evidence suggesting hyaluronic acid (HA) injections as effective in the treatment of tendinopathy, current recommendations about the management of this condition do not include this intervention. HA seems to be an effective therapeutic option for the management of sport-related tendinopathies, but further studies with a larger sample size are needed to confirm available findings. In this narrative review, we analyzed available literature about the rationale of the use of HA in the management of tendon injury and, particularly, in sport-related tendinopathies
Quality of Life and Sexual Health in the Aging of PCa Survivors.
Prostate cancer (PCa) is the most common malignancy in elderly men. The progressive ageing of the world male population will further increase the need for tailored assessment and treatment of PCa patients. The determinant role of androgens and sexual hormones for PCa growth and progression has been established. However, several trials on androgens and PCa are recently focused on urinary continence, quality of life, and sexual function, suggesting a new point of view on the whole endocrinological aspect of PCa. During aging, metabolic syndrome, including diabetes, hypertension, dyslipidemia, and central obesity, can be associated with a chronic, low-grade inflammation of the prostate and with changes in the sex steroid pathways. These factors may affect both the carcinogenesis processes and treatment outcomes of PCa. Any treatment for PCa can have a long-lasting negative impact on quality of life and sexual health, which should be assessed by validated self-reported questionnaires. In particular, sexual health, urinary continence, and bowel function can be worsened after prostatectomy, radiotherapy, or hormone treatment, mostly in the elderly population. In the present review we summarized the current knowledge on the role of hormones, metabolic features, and primary treatments for PCa on the quality of life and sexual health of elderly Pca survivors
Sviluppo di tecnologie innovative per l’identificazione, monitoraggio, remediation di sorgenti di contaminazione naturale e antropica
La tecnica di rilievo acustico multifascio (“multibeam bathymetry” o “swath bathymetry”) utilizza l’energia acustica per acquisire misure della profondità del fondale marino e rappresenta uno fra i metodi più efficaci di rilievo morfo-batimetrico, in quanto consente, in tempi relativamente brevi, di ottenere una notevolissima quantità di informazioni correttamente georeferenziate sui fondali investigati. Rispetto ai limiti dell’ecoscandaglio a fascio singolo, l’ecoscandaglio multifascio (MBES multibeam echosounder) offre sostanzialmente la possibilità di “riconoscere” e posizionare tutti gli arrivi laterali, sia quelli dovuti al moto della nave che quelli legati alla morfologia irregolare del fondo. Il Side Scan Sonar (SSS) viene utilizzato per la determinazione delle caratteristiche morfoacustiche dei fondali: Rappresenta un'applicazione differenziata del tradizionale principio dell'ecoscandaglio utilizzato per i sondaggi acustici batimetrici verticali, che viene adattato all'impiego per i sondaggi acustici con scansione areale. Il parametro misurato con i sistemi SSS è il backscatter, ovvero la riflessione delle onde dovuta alle caratteristiche di rugosità intrinseche dei materiali
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