Papers by Eugenio Pugliese Carratelli
Marine X-band radar based systems are well tested to provide information about sea state and bath... more Marine X-band radar based systems are well tested to provide information about sea state and bathymetry. It is also well known that complex geometries and non-uniform bathymetries provide a much bigger challenge than offshore scenarios. In order to tackle this issue a retrieval method is proposed, based on spatial partitioning of the data and the application of the Normalized Scalar Product (NSP), which is an innovative procedure for the joint estimation of bathymetry and surface currents. The strategy is then applied to radar data acquired around a harbour entrance, and results show that the reconstructed bathymetry compares well with ground truth data obtained by an echo-sounder campaign, thus proving the reliability of the whole procedure. The spectrum thus retrieved is then analysed to show the evidence of reflected waves from the harbour jetties, as confirmed by chain of hydrodynamic models of the sea wave field. The possibility of using a land based radar to reveal sea wave reflection is entirely new and may open up new operational applications of the system.
Marina di Rimini is located on the western shore of the Northern Adriatic. The marina itself prov... more Marina di Rimini is located on the western shore of the Northern Adriatic. The marina itself provides berthing for pleasure craft, and is accessed through a river channel which is trained several hundred metres into the sea. This layout is common along the Northern Adriatic coastline of Italy. On occasion, however, navigation along the river channel into the marina basin is thwarted by excess levels of wave disturbance. It has been proposed to modify the layout of the river training walls so that greater protection from waves, and therefore safer navigation into the marina, is achieved. The objective of the study reported in this paper was to examine the potential impact on the nearby shoreline of modifying the layout of the river training walls. Numerical models exploit our understanding of physical processes and it has become a standard requirement, in turn, to exploit numerical models when carrying out assessments of the effects of intervening at the coastline. The innovative met...
Liquid impact on planar surfaces is a challenging issue in many research fields. Under certain ci... more Liquid impact on planar surfaces is a challenging issue in many research fields. Under certain circumstances, these phenomena may occasionally produce high, spatially localized pressure peaks, thus inducing dangerous solicitations. The present work focuses on some relevant computational aspects of the fluid impact onto inclined planar surface, making use of the Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) Lagrangian technique. With reference to the early stages of the impact process, pressure distribution is described as function of the incident wave’s features and the angle of incidence of the solid surface assumed. Results are then discussed and compared with the corresponding ones obtained via Eulerian software. Key-Words: SPH, WCSPH, FSI, Slamming loads, Numerical methods in fluids
The design of breakwaters must be based on the full understanding of the interaction of a complex... more The design of breakwaters must be based on the full understanding of the interaction of a complex natural system (the sea and shores) with artificial structures (breakwaters). Typically, design work entails extensive physical modeling, which can be quite expensive and time-consuming. Until recently, the complex aspects of breakwater behavior were considered too challenging for detailed numerical simulations. This is especially the case for breakwaters consisting of rubble mounds composed of blocks of concrete or rocks in which water flows through complex paths with unsteady motion. Within this context, the problems induced by the rock mound have so far been treated by the sometimes simplistic “porous media” approach which assumes a filtration flow (Darcy or Forchheimer for a linear or quadratic loss, respectively) between the blocks
Satellite altimeter data provide useful information about short term oscillations of storm intens... more Satellite altimeter data provide useful information about short term oscillations of storm intensity, a phenomenon which might bear a relevant effect on the estimation of extreme value SWH. However, while such data are now easily and readily available, their application is not at all straightforward: problems like the size of the sampled area, the presence of rain and the influence of land or floating objects, may confuse the results and have to be taken into account. The paper and the discussion will deal with recent research in this field and will provide results on gustiness effects as estimated from both satellite data and wave meter measurement.
Altimeter data have been routinely assimilated and used to assess the reliability of wave forecas... more Altimeter data have been routinely assimilated and used to assess the reliability of wave forecasts for many years. A more recent application of such data is to provide an indication of Small Scale Storm Variability (SSSV) due to the irregular wind structure at the sea level (“gustiness”). Both gustiness and SSSV have been examined by using Jason - 1, Jason - 2 and ESA Envisat altimeter SWH data along passes in enclosed seas. Statistical parameters have been extracted and compared with similar statistics from state-of-the-art Meteo/Wave models. A variability is shown to exist on a scale as low as the resolution of altimeter data - i.e. down to a few kilometres - while weather and wave models - even those with the highest resolution - show a much smoother behaviour
Until recently, physical models were the only way to investigate into the details of breakwaters ... more Until recently, physical models were the only way to investigate into the details of breakwaters behavior under wave attack. From the numerical point of view, the complexity of the fluid dynamic processes involved has so far hindered the direct application of Navier-Stokes equations within the armour blocks, due to the complex geometry and the presence of strongly non stationary flows, free boundaries and turbulence. In the present work the most recent CFD technology is used to provide a new and more reliable approach to the design analysis of breakwaters, especially in connection with run-up and reflection. The solid structure is simulated within the numerical domain by overlapping individual virtual elements to form the empty spaces delimited by the blocks. Thus, by defining a fine computational grid, an adequate number of nodes is located within the interstices and a complete solution of the full hydrodynamic equations is carried out. In the work presented here the numerical simu...
From the numerical point of view, the complexity of the fluid dynamic processes involved has so f... more From the numerical point of view, the complexity of the fluid dynamic processes involved has so far hindered the direct application of Navier-Stokes equations within the armour blocks, due to the complex geometry and the presence of strongly non stationary flows, free boundaries and turbulence. In the present work the most recent CFD technology is used to provide a new and more reliable approach to the design analysis of breakwaters, especially in connection with run-up and overtopping.
International Journal of Naval Architecture and Ocean Engineering, 2018
The paper provides some developments of a numerical approach ("Numerical Calculation of Flow With... more The paper provides some developments of a numerical approach ("Numerical Calculation of Flow Within Armour Units", FWAU) to the design of rubble mound breakwaters. The hydrodynamics of wave induced flow within the interstices of concrete blocks is simulated by making use of advanced, but well tested, CFD techniques to integrate RANS equations. While computationally very heavy, FWAU is gaining ground, due to its obvious advantages over the "porous media", i.e. the possibility of accounting for the highly non stationary effects, the reduced need of ad hoc calibration of filtration parameters and also e in perspective e the evaluation of hydrodynamic forces on single blocks. FWAU however is a complex technique, and in order to turn it into a practical design tool, a number of difficulties have to be overcome. The paper presents recent results about this validation, as well as insight into fluid dynamical aspects.
Water, 2020
Calculating the significant wave height (SWH) in a given location as a function of the return tim... more Calculating the significant wave height (SWH) in a given location as a function of the return time is an essential tool of coastal and ocean engineering; such a calculation can be carried out by making use of the now widely available weather and wave model chains, which often lead to underestimating the results, or by means of in situ experimental data (mostly, wave buoys), which are only available in a limited number of sites. A procedure is hereby tested whereby the curves of extreme SWH as a function of the return time deriving from model data are integrated with the similar curves computed from buoy data. A considerable improvement in accuracy is gained by making use of this integrated procedure in all locations where buoy data series are not available or are not long enough for a correct estimation. A useful and general design tool has therefore been provided to derive the extreme value SWH for any point in a given area.
Journal of Marine Science and Engineering, 2020
The orbital velocity of sea wave particles affects the value of sea surface parameters as measure... more The orbital velocity of sea wave particles affects the value of sea surface parameters as measured by radar Doppler altimeters (also known as delay Doppler altimeter (DDA)). In DDA systems, the along-track resolution is attained by algorithms that take into account the Doppler shift induced by the component along the Earth/antenna direction of the satellite velocity, VS. Since the vertical component of the wave particle orbital velocity also induces an additional Doppler effect (in the following R-effect), an error arises on the positioning of the target on the sea surface. A numerical investigation shows that when the wavelength of sea waves is of the same order of magnitude of the altimeter resolution, the shape of the waveform might be significantly influenced by the R-effect. The phenomenon can be particularly important for the monitoring of long swells, such as those that often take place in the oceans.
Remote Sensing, 2018
This paper reports on an investigation on the influence of waves on the sea surface height error,... more This paper reports on an investigation on the influence of waves on the sea surface height error, σ h , as measured by Delay Doppler satellite altimetry (DDA). CryoSat-2 altimeter sea surface height (SSH) data in the North Sea, processed in both DDA and pseudo low resolution mode (PLRM), are correlated with European Centre for Medium-Range Weather Forecasts (ECMWF) co-located sea state data. We find a small, but consistent correlation between the 1 Hz standard deviation, σ h , of the 20 Hz altimeter SSH and the ECMWF total significant wave height, SWH t. The same analysis carried out between σ h and the swell component of the wave spectrum shows a smaller correlation. In contrast, the correlation between the PLRM σ h and any component of the SWH spectrum has not been found to be significant. To provide an explanation of these results, the aliasing effect caused by the interaction between the sea wavelength and the altimeter resolution has been considered; a simple model has, therefore, been produced to simulate the dependence of the aliasing-derived, σ A , on the sea wavelength. The alias/wavelength curve obtained helps to explain why-at least for the relatively low wavelength sea data considered-the wave direction and its wavelength have little or no influence on σ h .
Coastal Engineering Proceedings, 2017
It has been shown before, and it is intuitively evident, that in a Significant Wave Height (SWH) ... more It has been shown before, and it is intuitively evident, that in a Significant Wave Height (SWH) time series, the longer the sampling interval, the lower is the number of events which are above a given threshold value. As a consequence, the use of data with a low time resolution (such as a 3 h sampling, for instance) causes a considerable undervaluation of the extreme SWH values for a given return time RT. In this paper an example of such a bias is provided, and a method is suggested to estimate it on a regional basis. Results may help to improve the use of historical wave meters data which were often collected with a low time resolution, and may also provide a tool to improve the application of Numerical Meteo-Wave models to the evaluation of extremes.
Natural Hazards and Earth System Sciences Discussions, 2017
Extreme weather events have significant impacts on coastal human activities and related economy. ... more Extreme weather events have significant impacts on coastal human activities and related economy. In this scenario the forecast of sea storms and wave run-up events is a challenging goal to mitigate the wave effects on shores, piers and coastal structures. To do this, we used a computational model chain based on both community and ad hoc developed numerical models in an operational context to evaluate the beach inundation levels. At this aim, we compared the results of simulated and observed wave run-up levels on a micro-tidal beach located on the northern Tyrrhenian Sea. The offshore wave simulations have been performed by WaveWatch III model, implemented by Campania Center for Marine and Atmospheric Monitoring and Modelling (CCMMMA) – University of Naples Parthenope, which were used as initial conditions for run-up calculations using different formulas. The validation of the simulated waves was done with different observation systems. The offshore wave simulations were matche...
Ocean Science Discussions, 2016
The paper presents the results of an integrated buoy and X-Band radar sea state monitoring activi... more The paper presents the results of an integrated buoy and X-Band radar sea state monitoring activity carried out on the southern coast of Sicily. The work involved the integration of buoy and radar data, as well as the simultaneous acquisition of Significant Wave Height (SWH) values from two similar radar sets located at a slight distance from each othera rare and fortunate circumstance which took place during two storms in the winter 2014-2015. Good consistency and repeatability was reached between the two radars and the reliability of X-Band radar as a wave monitoring system was confirmed by the comparison with the buoy wave meter. A further and important result of the work is the knowledge gained on the short spatial and temporal fluctuations of the sea state: while such Small Scale Storm Variations (SSSV) cannot be easily discriminated from electromagnetic effects and from algorithm artefacts, some important progress has been done towards the identification of this phenomenon. Integration of different sensors is the key to a definite improvement of sea state monitoring for most coastal applications. 1 Introduction There can be no doubt about the ever growing importance of coastal monitoring from all points of view: biological, chemical, water quality, temperature, currents, etc. Among all the relevant parameters those concerning wave agitation ("the sea state") are, if not the most important, certainly the first to be considered, since they influence all the others, directly or indirectly. They also closely connected to the meteorological conditions, both on a global and a local scale. Wave height measurement is probably the most important monitoring activity being carried out on the sea. It has a great scientific and economical relevance [1,2] therefore an equally great effort is dedicated all over the world to the maintenance of complex network of measuring systems. Routine sea wave monitoring, is presently carried out by accelerometric or GPS buoys deployed mostly along the coasts. Satellite altimeters [3] and SAR radars [4,5], also play a very important role in offshore
Theoretical and Computational Fluid Dynamics, 2016
The sudden impact of a free surface flow upon a solid wall is a common occurrence in many situati... more The sudden impact of a free surface flow upon a solid wall is a common occurrence in many situations in nature and technology. The design of marine structures is probably the most obvious example, but also river and dam hydraulics as well as the necessity of understanding flood and debris flow-induced damage have led to theoretical and experimental work on the mechanism of fluid slamming loads. This is therefore a very old and rich research field, which has not yet reached full maturity, so that semi-empirical methods in design practice are still the rule in many sectors. Up-to-date CFD technology with both Eulerian and Lagrangian approaches is employed to investigate highly non-stationary fluid impact on a solid wall. The development of the pressure wave produced by the impact is examined as it propagates and interacts with the fluid boundaries, as well as the subsequent build-up of high-pressure gradients of high fluid velocities. The geometry and the velocity field of the problem considered are very simple, but the results seem to provide new insight, in particular, into the connection between phenomena with different timescales. Keywords Fluid impact • Smoothed particle hydrodynamics • Volume of fluid • Fluid-structure interaction • Free surface flows Communicated by Harindra Joseph Fernando.
Geophysical Monograph Series, 2011
Coastal Ocean Observing Systems, 2015
In the last few years, a number of land- and ship-based X-band radar systems have been developed ... more In the last few years, a number of land- and ship-based X-band radar systems have been developed to collect information on the sea state, i.e., on the significant wave height as well as on its spectral distribution. More recently, new techniques have been developed to estimate shallow water bathymetry, by taking into account the effects of depth on the dispersion of gravity waves. This chapter is aimed at reviewing such state-of-the-art algorithms and at providing some examples of applications of the most recent technique. It is shown that the accuracy is fairly adequate for shallow water, but it decreases significantly as the depth increases; besides, because the effects of stationary or nearly stationary currents interfere with the analysis, it is necessary to make use of algorithms that can estimate both depth and currents simultaneously.
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Papers by Eugenio Pugliese Carratelli