46 research outputs found
Comparative analyses between the zero-inertia and fully dynamic models of the shallow water equations for unsteady overland flow propagation
The shallow water equations are a mathematical tool widely applied for the simulation of
flow routing in rivers and floodplains, as well as for flood inundation mapping. The interest of many researchers has been focused on the study of simplified forms of the original set of equations. One of the most commonly applied simplifications consists in neglecting the inertial terms. The effects of such a choice on the outputs of the simulations of flooding events are controversial and are an important topic of debate. In the present paper, two numerical models recently proposed for the solution of the complete and zero-inertia forms of the shallow water equations, are applied to several unsteady flow routing scenarios. We simulate synthetic and laboratory scenarios of unsteady flow routing, starting from very simple geometries and gradually moving towards complex topographies. Unlike the studies of the range of validity of the zero-inertia model, based on a small perturbation of the linearized flow model, in unsteady flow propagation over irregular topographies, it is more difficult to specify criteria for the applicability of the simplified set of equations. Analyzing the role of the terms in the momentum equations, we try to understand the effect of neglecting the inertial terms in the zero-inertia formulation. We also analyze the
computational costs
Hydrothermal fluid venting in the offshore sector of Campi Flegrei caldera: A geochemical, geophysical, and volcanological study
The ongoing unrest at the Campi Flegrei caldera (CFc) in southern Italy is prompting exploration
of its poorly studied offshore sector. We report on a multidisciplinary investigation of the Secca delle
Fumose (SdF), a submarine relief known since antiquity as the largest degassing structure of the offshore
sector of CFc. We combined high-resolution morphobathymetric and seismostratigraphic data with onshore
geological information to propose that the present-day SdF morphology and structure developed during
the initial stages of the last CFc eruption at Monte Nuovo in AD 1538. We suggest that the SdF relief stands
on the eastern uplifted border of a N-S-trending graben-like structure formed during the shallow emplacement
of the Monte Nuovo feeding dike. We also infer that the high-angle bordering faults that generated
the SdF relief now preferentially allow the ascent of hot brines (with an equilibrium temperature of 1798C),
thereby sustaining hydrothermal degassing on the seafloor. Systematic vertical seawater profiling shows
that hydrothermal seafloor venting generates a sizeable CO2, pH, and temperature anomaly in the overlying
seawater column. Data for the seawater vertical profile can be used to estimate the CO2 and energy (heat)
outputs from the SdF area at 50 tons/d (0.53 kg/s) and 80 MW, respectively. In view of the cause-effect
relationship with the Monte Nuovo eruption, and the substantial gas and energy outputs, we consider that
the SdF hydrothermal system needs to be included in monitoring programs of the ongoing CFc unrest
The brain decade in debate: VIII. Peptide hormones and behavior: cholecystokinin and prolactin
Behavioral changes in Rattus norvegicus experimentally infected by Toxocara canis larvae
Misure di portata al colmo mediante analisi di livelli idrici in condizioni di moto vario
Multilevel model for flood wave propagation in flood-affected areas
A hyperbolic model for the simulation of flood wave propagation on initially dry land is presented. The convective inertia terms are neglected in the momentum equations. This assumption allows the use of a finite element scheme with linear shape functions for the free surface elevations and constant unit discharges inside each element. An appropriate use of the explicit and implicit approximation of the spatial derivatives is able to avoid the introduction of internal boundaries in the case of vertical discontinuities of the terrain elevation. This is obtained without losing the desirable features of the system matrix or limiting the maximum Courant number. The efficiency and the reliability of the proposed method are investigated for a flood in the south of Sicily, Italy, where a detailed description of the ground morphology has been proved to be essential for obtaining a good match between measured and computed maximum water depths