Search results for " Numerical modelling"

Effect of the junction angle on turbulent flow at a hydraulic confluence

2018

Despite the existing knowledge concerning the hydrodynamic processes at river junctions, there is still a lack of information regarding the particular case of low width and discharge ratios, which are the typical conditions of mountain river confluences. Aiming at filling this gap, laboratory and numerical experiments were conducted, comparing the results with literature findings. Ten different confluences from 45 ∘ to 90 ∘ were simulated to study the effects of the junction angle on the flow structure, using a numerical code that solves the 3D Reynolds Averaged Navier-Stokes (RANS) equations with the k- ϵ turbulence closure model. The results showed that the higher the junction angle, the …

SEWER PRESSURIZATION MODELLING BY A RIGID-COLUMN METHOD

2008

Mathematical modelling of pressurization transient by a rigid-column method is studied based on previous laboratory testing. Of course, such a method is not able to simulate the experimental intense pressure oscillations; however, it is considerably simpler than other feasible methods and more easily implementable within drainage network models. Starting from this operative point of view, the paper aims at recognizing “what” and “how much” of the transient can be simulated by a rigid-column method. Actually, better results were obtained than it was expected. The model proves to be successful in simulation of the filling pipe stage as well as the stabilization stage of flow to the final stea…

A numerical study on the effect of the interface material model on the tensile behaviour of FRCM strips

2019

Fibre Reinforced Cementitious Matrix (FRCM) composites are becoming increasingly popular for strengthening masonry structures for which the compatibility of the inorganic matrix with the chemical and physical properties of the support makes it advantageous to adopt such systems. However, despite the large use of FRCMs for strengthening applications, the characterization and modelling of the mechanical response in tension of these systems is an open issue. In fact, the constitutive tensile law of the composite shows to be affected by different variables, such as the clamping system adopted during tensile test, the gauge length used for recording strains, the monitoring of the number of yarns…

Rock decay phenomena and collapse processes in the “Latomiae del Paradiso” in Syracuse (Sicily)

2014

The Latomiae (origin: Greek latomia, from laas, las stone plus –tomia tomy ) del Paradiso in Syracuse are Magna Graecia rock quarries, located in the coastal areas of Southern Italy and internationally renowned for their impressive environment. The few historical technical records do not help clarify the events that led to their current configuration since a series of instability phenomena occurred due to decay processes over time. Through a geotechnical back-analysis, this work highlights the failure phenomena, which may have led to the current configuration of the easterly side of the Latomiae del Paradiso. The back-analysis process was carried out by means of numerical modelling, support…

Characterisation of submarine groundwater discharge offshore south-eastern Sicily

2005

A complex approach in characterisation of submarine groundwater discharge (SGD) off south-eastern Sicily comprising applications of radioactive and non-radioactive tracers, direct seepage measurements, geophysical surveys and a numerical modelling is presented. SGD fluxes in the Donnalucata boat basin were estimated by direct seepage measurements to be from 4 to 12Ls(-1), which are comparable with the total SGD flux in the basin of 17Ls(-1) obtained from radon measurements. The integrated SGD flux over the Donnalucata coast estimated on the basis of Ra isotopes was around 60m(3)s(-1) per km of the coast. Spatial variations of SGD were observed in the Donnalucata boat basin, the average (222…

Modelling steel jacketed RC columns: Remarks by experimental-numerical comparisons

2015

The recent large use of nonlinear seismic assessment techniques requires the definition of highly reliable computational models. The retrofitting or strengthening of RC columns by steel angles and battens is a commonly adopted technique, used to improve strength and deformation capacity of existing RC buildings. In the case of steel angles not directly loaded, the numerical definition of the cross-section model has to be handled carefully since it is affected by more uncertainties. The vertical load carried by the angles is a function of the lateral confinement pressure, the cohesion and the friction coefficient between the materials, parameters which are not always easy to predict. The pap…

Mathematical modelling of pressure oscillations in sewer pressurization

2008

The finite element implementation of 3D fractional viscoelastic constitutive models

2018

Abstract The aim of this paper is to present the implementation of 3D fractional viscoelastic constitutive theory presented in Alotta et al., 2016 [1]. Fractional viscoelastic models exactly reproduce the time dependent behaviour of real viscoelastic materials which exhibit a long “fading memory”. From an implementation point of view, this feature implies storing the stress/strain history throughout the simulations which may require a large amount of memory. We propose here a number of strategies to effectively limit the memory required. The form of the constitutive equations are summarized and the finite element implementation in a Newton-Raphson integration scheme is described in detail. …

Tsunami Vulnerability Evaluation for a Small Ancient Village on Eastern Sicily Coast

2022

The Ionian sea is prone to tsunamis due to its proximity to the Calabrian subduction zone, which is one of the major tsunamigenic areas of the Mediterranean. The tsunami disaster risk is, nowadays, significantly higher due to the increased exposure of buildings as a result of the economic and touristic growth of the Mediterranean coastal areas. This study focuses on Marzamemi, a small village in the western coast of Sicily, since its morphology and human presence amplify the need to assess its buildings’ vulnerability. The main objective of this research is to quantify the building vulnerability to tsunami hazards using a physical and realistic tsunami scenario. For this purpose, the relati…

4D paleoenvironmental evolution of the Early Triassic Sonoma Foreland Basin (western USA)

2017

In the wake of the Mesozoic, the Early Triassic (~251.95 Ma) corresponds to the aftermath of the most severe mass extinction of the Phanerozoic: the end-Permian crisis, when life was nearly obliterated (e.g., 90% of marine species disappeared). Consequences of this mass extinction are thought to have prevailed for several millions of years, implying a delayed recovery lasting the whole Early Triassic, if not more. Several paradigms have been established and associated to a delayed biotic recovery scenario expected to have resulted from harsh and deleterious paleoenvironments. These paradigms include a global anoxia in the marine realm, a “Lilliput” effect, and the presence of “disaster” tax…