LAURE , Patrice

A spectral approach is proposed to determine the flow field of a thin film inside narrow channels of arbitrary shape. Although the method is easily extended to transient flow, only steady flow is considered here. The flow field is represented spectrally in the depthwise direction in terms of orthonormal shape functions, which together with the...

Compression Moulding is used in automobile manufacturing and consists mainly in the compression of a composite preform in a mould. The preform is usually composed by the resin, the reinforcing fibres and other fillers. The process is rather simple but challenging from the numerical point of view. We have developed numerical methods able to...

Une méthode de simulation numérique directe a été développée pour l'écoulement de fluides fortement chargés, avec plusieurs populations de particules (fibres et sphères), pouvant entrer en collision. Ce fluide complexe modélise les écoulements de BMC (Bulk Molding Compound) utilisés par Schneider Electric. Une approche par domaines fictifs,...

Une méthode de simulation numérique directe a été développée pour l'écoulement de mélange de fluides newtoniens et de particules rigides de formes et tailles diverses. Elle est basée sur une approche par domaine fictif, qui consiste à étendre le domaine fluide au doamine occupé par les particules (Glowinski et al(1999)) . L'écoulement étant...

The first works devoted to the evolution of elongated particles are mainly due to Jeffery, which exhibits the evolution equation for orientation. In a simple shear flow and Newtonian fluid, the particle was found to undergo a periodic revolution, called the Jeffery orbit centered around the vorticity axis. This orbit is controlled by an aspect...

Contents: Introduction. Observations. Models. Computation of fibre orientation in injection moulding. Conclusions. References

Interfacial instabilities occurring in the coextrusion process of molten polymers have been widely studied. The theoretical work based on the stability of 2D Poiseuille multilayer flows (invariant along the flow motion) have pointed out the convective nature of this instability (it is either amplified or damped in the flow direction). This...

The flow of two superimposed Newtonian layers in a channel is investigated numerically in this study. The two-layer film flows inside a long channel due to a pressure gradient. The scaled conservation equations for two-layer incompressible Newtonian film flow are first introduced. The weighted residual approach first proposed by Amaouche [Phys....

Micro-injection molding is frequently used in micro-medical, micro-optic and micro-mechanics due to its effectiveness for mass production. This work focuses mainly on offering numerical tools to model the injection of textured molds. Such tools can predict the different filling scenarios of the micro-details and consequently offer optimal...

Tammisola et al (2012 J. Fluid Mech. 713 632-58) have observed a counter-intuitive destabilizing effect of the surface tension in planar wakes by means of a global linear analysis. In the present study, we conduct direct numerical simulation (DNS) of wakes of two immiscible fluids. The numerical scheme is based on a level set approach to track...

The chapter focuses on fibre reinforced thermoplastics or polymer composites which are mainly produced by injection and compression molding using particles having mostly cylindrical shape (short or long fibers made up of glass, carbon or flax). The aim of this fibre addition is to improve the mechanical properties of final parts. However these...

This chapter is dedicated to the simulation of composite forming processes. It concerns numerical methods for molding, at the different material scales, involving multiphysics analysis. From the different possible numerical techniques, we focus on a stabilized finite element method for the resolution of the continuum equations (mass, momentum...

TA Mixed Finite Element (MFE) method for 3D non-steady flow of a viscoelastic compressible fluid is presented. It was used to compute polymer injection flows in a complex mold cavity, which involves moving free surfaces. The flow equations were derived from the Navier-Stokes incompressible equations, and we extended a mixed finite element...

Micro-injection moulding is frequently used for the fabrication of devices in many different fields such as micro-medical technologies, micro-optics and micro-mechanics thanks to its effectiveness for mass production. This work focuses mainly on offering numerical methodology to model the injection into textured moulds. Such approach can...

La perméabilité d'un renfort tissé, utilisé dans les procédés LCM, est un paramètre significatif pour modéliser leur imprégnation. La tension de surface est un paramètre influant au cours de l'imprégnation. Une approche monolithique pour la résolution numérique d'écoulements multiphasiques est proposée et appliquée aux écoulements à l'échelle...

Mesh adaptation has proven to be very efficient for simulating transient multiphase computational fluid dynamics applications. In this work, we present a new parallel anisotropic mesh adaptation technique relying on an edge based error estimator. It provides a high level of accuracy while substantially reducing the computational effort. This...

Ce travail propose une approche multi-domaine pour modéliser l'écoulement d'un fluide complexe (un fluide de Bingham). Une attention plus particulière est portée à l'interface liquide-air et à l'orientation des fibres. Les applications concernent l'ajout de tiges de métal au béton liquide afin d'améliorer les propriétés mécaniques des...

An efficient method to compute permeability of fibrous media is presented. An immersed domain approach is used to represent the porous material at its microscopic scale and the flow motion is computed with a stabilized mixed finite element method. Therefore the Stokes equation is solved on the whole domain (including solid part) using a penalty...

Micro-injection moulding is frequently used for the mass production of devices in micro-medical technologies, micro-optics and micro-mechanics. This work focuses mainly on offering numerical tools to model the injection of micro-textured moulds. Such tools can predict the different filling scenarios of the micro-details and consequently offer...

This paper is devoted to the numerical study of the stability of the plane flow for two immiscible fluids obeying Maxwell constitutive equation in a channel of aspect ratio 8. For fixed viscosity and flow rate ratios, the shape and non-linear behavior of interfacial waves induced by small perturbations of the input flow rate are studied using...

The interface instability of the coextrusion flow of a polyethylene and a polystyrene is studied both experimentally and theoretically in a slit geometry. For prototype industrial conditions, we have found a stable/unstable transition which bounds the occurrence of stable/unstable sheets at die exit. By investigating a large range of processing...

See http://hal.archives-ouvertes.fr/docs/00/59/28/28/ANNEX/r_X8K316T9.pdf

This paper is devoted the behavior of suspension of fiber-spheres particles. We pointed out by experimental and numerical observations that the Jeferry approximation is no more valid as the sphere particle concentration increases.

The stability of two-layer flow of polyethylene and polystyrene is experimentally studied in different flow geometries and for various flow rate ratios. A first coextrusion device allows to stop the coextrusion flow in a very long slit channel, to cool down the polymer sample and to dismantle the die in order to extract extrudate which is then...

Dans un fluide Newtonien, l'orientation d'une fibre est parfaitement décrire par l'équation de Jeffery. Dans cette étude,on utilise un rhéomètre numérique pour étudier l'évolution d'une fibre dans un champ de cisaillement simple pour des fluidesviscoélastiques Oldroyd-B. Pour les fluides viscoélastiques, la période de rotation augmente avec le...