Search results for "fluid mechanics"

The Mach cone signal and energy deposition scenarios in linearized hydrodynamics

2010

Particle correlation measurements associated with a hard or semi-hard trigger in heavy-ion collisions may reflect Mach cone shockwaves excited in the bulk medium by partonic energy loss. This is of great interest because, when compared with theory, such measurements can provide information on the transport properties of the medium. Specifically, the formation of Mach cone shockwaves is sensitive to the viscosity and speed of sound, as well as the detailed nature of the jet medium interaction. However, modeling the physics of shockwave excitation to obtain a meaningful comparison with the measured correlations is very challenging since the correlations arise from an interplay of perturbative…

Advances in designing drip irrigation laterals

2018

It is known that using paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency (WUE). Recently, an analytical procedure to optimally design paired drip laterals on uniform slopes was proposed. More recently, this design procedure was simplified by deriving simple explicit relationships, as a function of 16 calibration constants, with relative errors that were less than 2%. In this paper, further simple design relationships are derived that require only 3 calibration constants, thus more readily obtainable results are produced and the influence of the flow rate and diameter exponents of resistance eq…

A flux based conservation approach for acoustic problems

2008

International audience

Galerkin and control-volume FEMs evaluation for acoustic problems

2004

International audience

Analyse de la dispersion de la solution MVCEF pour l'équation de Helmholtz

2006

CFD simulations

2022

Towards a rapidly rotating liquid sodium dynamo experiment

2002

The main characteristics of the Earth's dynamo are reviewed. The combined actions of Coriolisand Lorentz forces lead to the so--called ``magnetostrophic'' regime. We derive an estimate of the power needed to sustain the magnetic field in this regime. We show that an experimentwith liquid sodium can be designed to operate in the magnetostrophic regime. Such an experiment would bring most valuable informations on the mechanisms of planetary dynamos. In order toprepare this large--scale experiment and explore the magnetostrophic balance, a smaller scale liquid sodium set--up has been designed and is being built. It consists of a rapidly rotating spherical shell filled with liquid sodium, in wh…

Prédiction de cycle et stratégie de gestion énergétique basée sur une méthode d’optimisation globale

2017

International audience; La nécessité de prédire le cycle de conduite d’un automobiliste afin d’améliorer sa gestion énergétique et ainsi réduire la consommation de carburant a été démontré (Debert, Quigley). Dès lors, il serait aisé d’appliquer une méthode d’optimisation globale, telle que la Programmation Dynamique (DP en anglais), pour obtenir la stratégie optimale. Cette méthode est déjà utilisée dans de nombreuses applications (Sciarretta), mais au quotidien nombreux sont les facteurs environnants qui peuvent perturber les conditions de circulation (météo, travaux, accidents....) et impacter le cycle de conduite. Il est donc nécessaire d’élaborer une stratégie adaptative en temps réel. …

Numerical modeling of blood flow in the internal jugular vein with the use of computational fluid mechanics software.

2021

ObjectivesTo determine the site and nature of altered hemodynamics in pathological internal jugular veins.MethodWith the use of computational fluid mechanics software we simulated blood flow in 3 D models of the internal jugular veins that exhibited different morphologies, including nozzle-like strictures in their upper parts and valves in the lower parts.ResultsIn a majority of models with nozzle-like strictures, especially those positioned asymmetrically, abnormal flow pattern was revealed, with significant flow separation and regions with reversed flow. Abnormal valves had no significant impact on flow in a case of already altered flow evoked by stricture in upper part of the vein.Conclu…

Large-eddy simulations of turbulent flow with heat transfer in simple and complex geometries using Harwell-FLOW3D

1996

Abstract Large-eddy simulation (LES) results are presented and discussed for the turbulent flow with heat transfer in different geometrical configurations, including a plane channel, a channel bearing transverse square ribs on one of the walls, and a crossed-corrugated air heater. They were obtained using the computational fluid dynamics (CFD) code Harwell-FLOW3D (Release 2), finite-volume grids having up to 423 nodes, and the Smagorinsky subgrid model with several variants regarding near-wall damping and wall boundary conditions. The first problem (plane turbulent Poiseuille flow with heat transfer) was mainly used as a benchmark to investigate the influence of numerical methods (pressure-…