Search results for "numerical modelling"

High-resolution numerical modelling of the barotropic tides in the Gulf of Gabes, eastern Mediterranean Sea (Tunisia)

2017

International audience; A high-resolution 2D barotropic tidal model was developed for the Gulf of Gabes and used to characterise hydrodynamic processes and tidal dynamics. The model is based on the Regional Ocean Modelling System. It is forced at the open boundaries by the semidiurnal M2 and S2 astronomical components while meteorological forcing has been neglected. The model results show good agreement with observations confirming that it reproduces the gulf's main tidal characteristics reasonably well. In fact, the simulated semidiurnal tidal components M2 and S2 generate important sea level variations and coastal currents. Tidal propagation is directed to the gulf's western sector while …

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…

Numerical modeling and validation of hydrothermal liquefaction of a lignin particle for biocrude production

2021

Abstract Lignin liquefaction process under catalyst-free conditions in a temperature range from 573 K to 647 K is investigated with this mathematical model. Based on the theoretical understanding of the physical and chemical processes of the liquefaction process in subcritical temperatures, a comprehensive mathematical model for the decomposition of lignin by hydrolysis reaction pathway is developed on the results of a series of batch experiments. The model consists of four main sections. They are liquefaction of lignin particle, oily film, and inorganic (ash) layer formation behavior during the liquefaction, kinetic model to model further liquefaction process of initial products, and the l…

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

Polarity-reversal subduction zone initiation triggered by buoyant plateau obstruction

2022

Abstract Oceanic lithosphere worldwide is younger than ca. 200 Myr, suggesting that it must have been globally recycled by the recurrent formation of new subduction zones since the existence of subduction on Earth. However, postulated subduction zone initiation processes remain difficult to explain in many cases, and the specific geodynamic conditions under which these might occur are still largely unknown. We here use numerical models driven by the internal force balance of a subduction system to better understand the (geo)dynamics governing (intra-oceanic) polarity-reversal subduction zone initiation. This initiation mode assumes that the birth of a new subduction zone could be triggered …

Modelling of laser beam texturing process: experimental and numerical approaches

2007

The aim of this work is to reache a better control of the laser beam surface texturing process on three materials: 304L, TA6V and AA6056 alloys. For this purpose, two complementary methods, experimental and numerical modelling, have been used. As a result of the experimental design approach, it was observed that the laser surface texturing process of 304L and TA6V alloys is strongly influenced by the pulse energy and frequency. In order to obtain a surface roughness Sa < 5 µm for the highest possible productivity it is necessary to work with an energy of 5 mJ and a frequency ranging between 10 and 12 kHz. Unfortunately, for aluminium alloy AA6056, it is necessary to make a choice between ha…

SPH NUMERICAL MODELLING OF WAVE-STRUCTURE INTERACTION

The present thesis aims at contributing to a better understanding and modelling of flow driven by wave propagation approaching artificial or natural structures. From a physical point of view, a simplistic descrip- tion of the interaction of sea waves with a coastal structure can be given as the result of all processes felt by the waves which, propagating from offshore to nearshore, impact on the structure itself. Indeed, as sea waves approach a shore, the motion they generate deep down begins to interact with the sea bed. This slows the waves down and causes the crests in a series of waves to bunch up; this effect is called shoaling. The period of the waves does not change, but their height…

Influence of the channel design on the heat and mass exchange of induction channel furnace

2011

PurposeThe purpose of this paper is to present in‐depth numerical modelling of heat and mass exchange in industrial induction channel furnace (ICF).Design/methodology/approachThe turbulent heat and mass exchange in the melt is calculated using a three‐dimensional (3D) electromagnetic model and a 3D transient large eddy simulation method. The simulation model has been verified by flow velocity and temperature measurements, which were carried out using an industrial sized channel inductor operating with Wood's metal as a low temperature model melt.FindingsThe ICF is well‐established for melting, holding and casting in the metallurgical industry. But there are still open questions regarding th…

Ability of Preissmann slot scheme to simulate smooth pressurisation transient in sewers

2010

Urban drainage networks are generally designed to operate in a free-surface flow condition. However, as a consequence of heavy rainfall events or network malfunctioning, filling of sewers (pressurization) and network overflowing may occur. Several softwares are commonly used to simulate floods in drainage networks and their results are usually thought to be reliable and robust. However, no specific studies have been carried out on the behaviour of these softwares during the pressurization transient. Actually, mathematical models based on the momentum equation appear to be more suitable in correctly simulating the pressurization moving jump but models based on the energy equation are much mo…