A5043990814- Fluid Dynamics and Turbulent Flows
- Rheology and Fluid Dynamics Studies
- Fluid Dynamics and Vibration Analysis
- Fluid Dynamics and Thin Films
- Fluid Dynamics and Heat Transfer
- Plant Water Relations and Carbon Dynamics
- Wind and Air Flow Studies
- Heat Transfer Mechanisms
- Surface Modification and Superhydrophobicity
- Particle Dynamics in Fluid Flows
- Polymer crystallization and properties
- Nanofluid Flow and Heat Transfer
- Additive Manufacturing and 3D Printing Technologies
- Electrohydrodynamics and Fluid Dynamics
- Meteorological Phenomena and Simulations
- Reservoir Engineering and Simulation Methods
- Material Dynamics and Properties
- Fluid Dynamics and Mixing
- Hydrogels: synthesis, properties, applications
- Thermochemical Biomass Conversion Processes
- Natural Fiber Reinforced Composites
- Hydraulic flow and structures
- Fluid Dynamics Simulations and Interactions
- Ultrasound Imaging and Elastography
- Photoacoustic and Ultrasonic Imaging
Centre National de la Recherche Scientifique
2015-2024
Conservatoire National des Arts et Métiers
2005-2024
Laboratoire Procédés et Ingénierie en Mécanique et Matériaux
2005-2024
HESAM Université
2019-2024
École nationale supérieure d'arts et métiers
2005-2024
ParisTech
2021-2024
Centre National de la Recherche Scientifique et Technologique
2024
Centre National pour la Recherche Scientifique et Technique (CNRST)
2023
Université Le Havre Normandie
2013-2021
Laboratoire Ondes et Milieux Complexes
2013-2021
A novel experiment has been devised which provides direct evidence for critical point behavior in the longstanding problem of transition to turbulence a pipe. The novelty lies quenching by reducing Reynolds number and observing decay disordered motion. Divergence time scales implies underlying deterministic dynamics are analogous those found boundary crises dynamical systems. modulated wave packet emerges from long term transients this coherent state connections with recent theoretical developments.
As appreciated by those familiar with disposable diapers, polymeric hydrogels swell to absorb a remarkable amount of liquid. Although gels are widely used in many applications from moisture control drug delivery, the mechanisms fluid uptake and release complex, highly nonlinear, not well understood. The authors use modeling experiment show that processes swelling drying inherently transient dynamic---and strikingly different each other.
We report the results of an experimental study finite-amplitude thresholds for transition to turbulence in a constant mass flux pipe flow. The flow was perturbed using small impulsive jets and push–pull disturbances from holes wall. disturbance is used define amplitude perturbation critical value required cause scales proportion Re −1 jets. In this case, catastrophic scaling suggests simple balance between inertia viscosity. On other hand, threshold as −1.3 or −1.5 with precise depending on...
Results are reported on an experimental study of the rheology hydrate-forming water-in-oil emulsions. Density-matched concentrated emulsions were quenched by reducing temperature and irreversible transition was observed where viscosity increased dramatically. The have characteristic times for abrupt change dependent only temperature, reflecting importance effect subcooling. Mechanical hydrate-free may require longer depends shear rate, occurring more rapidly at higher rates but with...
Purpose Fluid flows in pipes whose cross-sectional area are increasing the stream-wise direction prone to separation of recirculation region. This paper aims investigate such fluid flow expansion pipe systems using direct numerical simulations. The circular diverging with different half angles, namely, 45, 26, 14, 7.2 and 4.7 degrees, considered. is fed by a fully developed laminar parabolic velocity profile at its inlet connected long straight downstream characterise zone skin friction...
The results of an experimental investigation granular segregation in a thin rotating drum are presented. A mechanism based on the presence uphill wave particles has been found to govern observed pattern petals. Specifically we develop simple model that captures essential physics and yields algebraic expression predicts number petals pattern.
We present an experimental study of disordered packings deformable spheres. Fluorescent hydrogel spheres immersed in water together with a tomography technique enabled the imaging three-dimensional arrangement. The mechanical behavior single subjected to compression is first examined. Then properties randomized collection box moving lid are tested. transition state where packing withstands finite stresses before yielding observed. Starting from random packed states, power law dependence...
Abstract Torque measurements in Taylor–Couette flow, with large radius ratio and aspect ratio, over a range of velocities up to Reynolds number 24 000 are presented. Following specific procedure, nine states distinct numbers vortices along the axis were found ratios measured. The relationship between speed torque for given is reported. In turbulent Taylor vortex flow regime, at relatively high number, change behaviour observed corresponding intersections torque–speed curves different states....
Abstract This study aims to analyze the effect of processing parameters, particularly cooling rate, on morphology and mechanical properties reinforced glass fiber polypropylene (GF‐PP) films. To achieve objective, a multi‐scale analysis was performed different neat PP films obtained by controlling thermal condition during fabrication process. Films with thickness about 100 μm have been prepared observe crystalline microstructure's formation follow its kinetics scale spherulites. The same...
There have been many investigations of the stability Hagen–Poiseuille flow in 125 years since Osborne Reynolds' famous experiments on transition to turbulence a pipe, and yet pipe problem remains focus attention much research. Here, we discuss recent results from experimental numerical obtained this new century. Progress has made three fundamental issues: threshold amplitude disturbances required trigger laminar state; Reynolds number below which disturbance decays state, with quantitative...
We report the results of a combined experimental and numerical study specific finite-amplitude disturbances for transition to turbulence in flow through circular pipe with sudden expansion. The critical amplitude thresholds localized turbulent patch downstream expansion scale Reynolds number power law exponent −2.3 experiments −2.8 simulations. A new mechanism periodic bursting recirculation region is uncovered where asymmetric develops dynamics: secondary breaks symmetry along wall bursts...
Microbubble generation techniques have been proposed in former investigations. Here, we study an effective technique using air bubbly flow into a convergent-divergent nozzle (venturi tube). Pressure change the diverging section induces bubble breakup. The purpose of this is to clarify effect velocity at throat with respect breakup process and behavior venturi tube. Relations between generated diameter are also described. Using high speed camera for detailed observation behavior, following...
Liquid nanofilms are ubiquitous in nature and technology, their equilibrium out-of-equilibrium dynamics key to a multitude of phenomena processes. We numerically study the evolution rupture viscous nanometric films, incorporating effects surface tension, van der waals forces, thermal fluctuations shear. show that create perturbations can trigger film rupture, but they do not significantly affect growth rate perturbations. The time be predicted from linear stability analysis governing thin...
Results are presented of an experimental investigation into patterned size segregation binary granular mixtures in a thin rotating drum that is half full. It observed streaks small particles formed within regions large ones where the integer number fixed over range rotation rate drum. Different patterns form adjacent parameter ranges and dynamics associated with exchange between neighboring states analyzed using angular spatiotemporal diagrams. These help to reveal properties merging...
We report the results of three-dimensional direct numerical simulations for incompressible viscous fluid in a circular pipe flow with gradual expansion. At inlet, parabolic velocity profile is applied together constant finite-amplitude perturbation to represent experimental imperfections. Initially, at low Reynolds number, solution steady. As number increased, length recirculation region near wall grows linearly. Then, critical symmetry-breaking bifurcation occurs, where linear growth...