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In this paper numerical computations dedicated to the analysis of the maneuvering behavior of a fully appended submarine are presented. The work presented here is part of the CNR-INSEAN activities scheduled in the framework of a joint Italian and Norwegian MoDs project, with the partnership of MARINTEK, under the egida of the European Defence Agency. The aim of the numerical work is to exploit the effect of cruciform and X rudder configuration on the turning qualities of the submarine in two operation conditions, namely open water and snorkeling depth. In this paper, the free running turning circle maneuver is analyzed; predictions are achieved by an in-house CFD solver.

In this paper numerical computations dedicated to the analysis of the maneuvering behavior of a fully appended submarine are presented. The work presented here is part of the CNR-INSEAN activities scheduled in the framework of a joint Italian and Norwegian MoDs project, with the partnership of MARINTEK, under the egida of the European Defence Agency. The aim of the numerical work is to exploit the effect of cruciform and X rudder configuration on the course stability qualities of the submarine in two operation conditions, namely open water and close to the free surface.

In this paper a coupled experimental and numerical activity dedicated to the analysis of the maneuvering behavior of a fully appended submarine is presented. The work presented here is part of the CNR-INSEAN activities scheduled in the framework of a joint Italian and Norwegian MoDs project, with the partnership of MARINTEK, under the egida of the European Defence Agency. The aim of the experimental work is mostly the collection of valuable data set for CFD benchmarking and the hydrodynamic characterization of the aft planes. Tests were carried out for two different stern appendage layouts (namely a cruciform and a X rudder configuration), allowing a comparison of the maneuverability capabilities between the two configurations. CFD studies were mainly devoted to the analysis of the flow field around the submarine and to collect hydrodynamic coefficients required by an in-house System Based Maneuvering solver. The latter has been used to perform two free running, self-propelled, maneuvers on the vertical plane.

This paper first presents a duration-dependent hypothesis regarding the parameters of the two component extreme value (TCEV) distribution and proposes a simple model to obtain the rainfall depth-duration relationship both at ungauged sites and at short record gauged sites in the Sicilian region. Then, by using the annual maximum peak flood and the annual maximum mean daily discharge recorded in Sicily, a TCEV hierarchical regional procedure is developed. An empirical estimation criterion which links the mean annual flood with the watershed area, and a modified rational formula in which a mean runoff coefficient is introduced, are proposed. Finally, two relationships are established for estimating the mean runoff coefficient, making use of the permeable watershed area and the wooded area.

The LAI is a key parameter in hydrological processes, especially in the physically based distribution models. It is a critical ecosystem attribute since physiological processes such as photosynthesis, transpiration and evaporation depend on it. The diffusion of water vapor, momentum, heat and light through the canopy is regulated by the distribution and density of the leaves, branches, twigs and stems. The LAI influences the sensible heat flux H in the surface energy balance single source models through the calculation of the roughness length and of the displacement height. The aerodynamic resistance between the soil and within-canopy source height is a function of the LAI through the roughness length. This research carried out a sensitivity analysis of some of the most important parameters of surface energy balance models to the LAI time variation, in order to take into account the effects of the LAI variation with the phenological period. Finally empirical retrieved relationships between field spectroradiometric data and the field LAI measured via a light-sensitive instrument are presented for a cereal field.

In the original publication of the article, the first and last names of the authors are interchanged and published incorrectly. The correct author names are given below: Paola Pennisi, Laura Giallongo, Giusy Milintenda, Michela Cannarozzo., (© 2021. Marta Olivetti Belardinelli and Springer-Verlag GmbH Germany, part of Springer Nature.)