A5042930756- Fluid Dynamics and Thin Films
- Fluid Dynamics and Heat Transfer
- Surface Modification and Superhydrophobicity
- Nanomaterials and Printing Technologies
- Electrohydrodynamics and Fluid Dynamics
- Heat Transfer and Boiling Studies
- Nonlinear Dynamics and Pattern Formation
- Microfluidic and Bio-sensing Technologies
- Fluid Dynamics and Mixing
- nanoparticles nucleation surface interactions
- Adhesion, Friction, and Surface Interactions
- Phase Equilibria and Thermodynamics
- Fluid Dynamics and Turbulent Flows
- Innovative Microfluidic and Catalytic Techniques Innovation
- Ocean Waves and Remote Sensing
- Advanced Thermodynamics and Statistical Mechanics
- Plant Surface Properties and Treatments
- Microfluidic and Capillary Electrophoresis Applications
- Spacecraft and Cryogenic Technologies
- Pickering emulsions and particle stabilization
- Solidification and crystal growth phenomena
- Particle Dynamics in Fluid Flows
- Coastal and Marine Dynamics
- Advanced Mathematical Physics Problems
- Aerosol Filtration and Electrostatic Precipitation
Université Libre de Bruxelles
2015-2024
University of Southern California
2002-2011
Universidad Complutense de Madrid
1995-2000
Institute for Problems in Mechanics
1992
The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring vapor concentration field around droplet with digital holographic interferometry. As a concrete example, an freely receding pending 3M Novec HFE-7000 analyzed at ambient conditions. measured cloud to deviate significantly from pure-diffusion regime calculation, but compares favorably new...
This publication lays the foundation for description of Multiscale Boiling Experiment, which was conducted within two measurement campaigns on International Space Station between 2019 and 2021. The experiment addresses fundamental questions about two-phase heat transfer during boiling processes. For this purpose, single or few subsequential bubbles are selectively ignited a heated substrate using short laser pulse. A detailed investigation phenomena is possible, as process temporally slowed...
We here present a simple fitting-parameter-free theory of the Leidenfrost effect (droplet levitation above superheated plate) covering full range stable shapes, i.e., from small quasispherical droplets to larger puddles floating on pocketlike vapor film. The geometry this film is found be in excellent quantitative agreement with interferometric measurements Burton et al. [Phys. Rev. Lett. 109, 074301 (2012)]. also obtain new scalings generalizing classical ones derived by Biance Fluids 15,...
Freely receding evaporating sessile droplets of perfectly wetting liquids, for which the observed finite contact angles are attributed to evaporation, studied with a Mach-Zehnder interferometer. The experimentally obtained droplet shapes found depart, under some conditions, from classical macroscopic static profile droplet. deviations (or absence thereof) explained in terms Marangoni flow due evaporation-induced thermal gradients along liquid-air interface. When such effect is strong,...
When a liquid drop is placed on highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon referred to as the Leidenfrost effect. The thermally insulating vapour film results in severe reduction of heat transfer rate compared experiments at lower surface temperatures, where direct contact with solid surface. A commonly made assumption that this isothermal, which least questionable for materials low thermal conductivity, resulting an overestimation...
For a liquid advancing or receding on flat bare solid in vapor atmosphere, we show that no singularities fact arise at the contact (triple) line. Contrary to common expectations, this does not require any ``regularizing'' microscopic effect (such as slip substrate, disjoining pressure precursor films). The key here is Kelvin effect, i.e., curvature-induced variation of saturation conditions. Importantly, evaporation-related appear either. We proceed within lubrication approximation and...
As originally realized by Nyborg ( J. Acoust. Soc. Am. , vol. 30, 1958, p. 329), the problem of inner acoustic/steady streaming can be analysed in quite general terms. The is one that develops high-frequency limit a thin Stokes (shear-wave) layer at boundary, contrast to outer main bulk fluid. analysis provides relevant inner-streaming characteristics through given distribution acoustic amplitude along boundary. Here such generalized treatment revisited for motionless By working terms...
We theoretically investigate the behavior of Leidenfrost drops on a flat substrate submitted to horizontal thermal gradient and highlight that they are able self-propel in preferential direction. Namely, found travel towards colder parts substrate, as if were trying maximize their lifetime. In particular, centimetric water drop can reach velocities order cm/s for gradients few K/mm. general, presented model, based upon lubrication approximation vapor cushion work Sobac et al. [“Leidenfrost...
The microstructure of a contact line formed by liquid and its pure vapor on perfectly wetted superheated smooth substrate, with the disjoining pressure most often in form positive inverse cubic law (nonpolar case), is routinely considered to end up microfilm extended over adjacent "dry" parts solid surface. Invoking spreading coefficient as an additional independent parameter within this framework, we argue however that regime truncated chosen instead if decreased below (still perfect...
Understanding the behavior of sessile drops can be rewarding in many applications while also fostering progress rapidly evolving field capillarity and wetting. Our experiments reveal that two evaporating on a solid substrate do attract even if, unlike binary-liquid recently studied literature [Cira et al., Nature, 2015], they are made same pure liquid. Several perfectly wetting liquids different volatilities tested to unveil quantify mechanisms enabling droplets communicate. While all recent...
During the spreading of a liquid over solid substrate, contact line can stay pinned at sharp edges until angle exceeds critical value. At (or sufficiently near) equilibrium, this is known as Gibbs' criterion. Here, we show both experimentally and theoretically that, for completely wetting volatile liquids, there also exists dynamically-produced contribution to depinning, which increases with evaporation rate. This suggests that one may introduce simple modification criterion (de)pinning...
In a study of the Leidenfrost levitation droplet on hot liquid bath, rather than, classically, an extremely plate, existential feedback is revealed. The induces bath flow, whose fickle structure explored both experimentally and theoretically. turn, flow drastically enhances heat transfer to by convective means, thus ensuring such evaporative despite poorly conducting medium bath.
An oscillatory instability mechanism is identified for a horizontal liquid layer with undeformable open surface heated from the air side. Although buoyancy and tension gradients are expected to play stabilizing role in this situation, we show that, acting together, they may lead of motionless state system. The consequence coupling between internal waves, whose resonant interaction resulting mode mixing discussed. Predictions amenable experimental test given together thorough analytical...
Steady (acoustic) streaming around a rigid oblate spheroid is studied in the incompressible limit when fluid medium and particle are small-amplitude high-frequency relative oscillatory motion along symmetry axis of spheroid. The inner (inside thin Stokes shear-wave layer) outer patterns analysed. A solution for obtained analytically small Reynolds numbers. At large numbers, boundary-layer consideration carried out. disk limit, as approached within family spheroids, systematically...
On the basis of a standard one-sided lubrication-type model, an analysis is carried out pertaining to small vicinity contact line volatile nonpolar perfectly wetting macroscopic liquid sample surrounded with its pure vapor and attached smooth uniformly superheated solid surface. The behavior film governed by effects evaporation, capillarity, disjoining pressure. kinetic resistance as well dependence local saturation temperature on pressure are accounted for. Within localized approach...
The contact line of a volatile liquid on flat substrate is studied theoretically. We show that remarkable result obtained for pure-vapour atmosphere ( Phys. Rev. E, vol. 87, 2013, 010401) also holds an isothermal diffusion-limited vapour exchange with air. Namely, both zero and finite Young’s angles, the motion- phase-change-related contact-line singularities can in principle be regularised solely by Kelvin effect (curvature dependence saturation conditions). latter prevents curvature from...
We consider the dynamics of an axisymmetric, partially wetting droplet a one-component volatile liquid. The is supported on smooth superheated substrate and evaporates into pure vapour atmosphere. In this process, we take liquid properties to be constant assume that phase has poor thermal conductivity small dynamic viscosity so may decouple its from phase. This leads so-called ‘one-sided’ lubrication-type model for evolution thickness, which accounts effects evaporation, capillarity,...