F. De Serio

Vertical dense jet in flowing current

The discharge of brackish water, as a dense jet in a natural water body, by the osmotic power plants, undergoes complex mixing processes and has significant environmental impacts. This paper focuses on the mixing processes that develop when a dense round jet outfall perpendicularly enters a shallow flowing current. Extensive experimental measurements of both the salinity and the velocity flow fields were conducted to investigate the hydrodynamic jet behavior within the ambient current. Experiments were carried out in a closed circuit flume at the Coastal Engineering Laboratory (LIC) of the Technical University of Bari (Italy). The salinity concentration and velocity fields were analyzed, providing a more thorough knowledge about the main features of the jet behavior within the ambient flow, such as the jet penetration, spreading, dilution, terminal rise height and its impact point with the flume lower boundary. In this study, special attention is given to understand and confirm the conjecture, not yet experimentally demonstrated, of the development and orientation of the jet vortex structures. Results show that the dense jet is almost characterized by two distinct phases: a rapid ascent phase and a gradually descent phase. The measured flow velocity fields definitely confirm the formation of the counter-rotating vortices pair, within the jet cross-section, during both the ascent and descent phases. Nevertheless, the experimental results show that the counter-rotating vortices pair of both phases (ascent and descent) are of opposite rotational direction.

Semi enclosed basin monitoring and analysis of meteo, wave, tide and current data: Sea monitoring

The present paper aims to show and discuss the long term and continuous recordings of both meteorological and hydrodynamic data collected in a semi enclosed sea. The site in question is composed by the Mar Grande and Mar Piccolo basins (Southern Italy), which are mutually connected. In turn, the Mar Grande is joined to the Ionian Sea by means of two openings. Therefore, the system shows features typical of a lagunar environment, which is also affected by coastal heavy industry and anthropic pressure, thus being highly vulnerable. A monitoring of its hydrodynamics could be useful, allowing both to check the real-time status of the basin and promptly intervene when accidents occur and to create a dataset necessary to calibrate and validate modelling systems providing forecasts. To this, in the framework of the Italian flagship Project RITMARE, a meteo-oceanographic station, a wave-current meter and a tide gauge have been installed in the area, since December 2013. In detail, measurements of wind, waves, tides and current profiles, are acquired on site with different sampling frequencies and are transmitted on a web cloud by a router 3G, where they are stored, thus being available for download by remote users. The data acquisition and processing is managed by the research group of the Department of Civil, Environmental, Building, Engineering and Chemistry (Technical University of Bari). All the acquired data are archived in monthly time-series, examined and discussed. The analysis of currents is made in two different measuring stations for the whole year 2015, as well as the analysis of wave data. On the contrary, tide data have been assessing only recently, since August 2015. Comparisons with available recordings of the year 2014 are examined. Also spatial and temporal correlations of both waves and currents are discussed. Finally, tidal trends are shown, consistent with current inversions.

Investigation of the current circulation offshore Taranto by using field measurements and numerical model

The goal of the present work is to show how measured current data could be used to improve mathematical hydrodynamic modelling. Some current field measurements assessed offshore Taranto, a city placed in Southern Italy, were utilized in conjunction with numerical simulations to reproduce some circulation patterns. Field measurements were carried out on 29/12/2006 by means of a Vessel Mounted Acoustic Doppler Current Profiler (VM-ADCP). Measurements were acquired at nine stations offshore Taranto into the homonymous gulf. The Northern and Eastern components of the water velocity provided the horizontal field of motion at various depths. The comparison between field measurements of sea currents and the results of the MIKE 3 FM HD model (by DHY) was analyzed. In order to achieve a good agreement between the measured and numerical data, a model calibration was carried out. It was pointed out that the tuning of the seabed roughness and of the wind stress factor was necessary to achieve a good overlapping between the measurements and the computed data. The calibrated numerical model may also be used as starting point for further simulations and for future ecological model in such a sensitive area.

Micrometeorological simulations over a coastal area using CALMET model: Atmosphere monitoring

This paper describes numerical experiments conducted by using the meteorological model CALMET. The aim is to assess how the computational time of the model runs depends on user-defined parameters involved in the iterative procedure used by CALMET to solve the meteorological field. The influence of the weather conditions on the simulation time has been also evaluated.