Marie-Jean Thoraval

Marie-Jean Thoraval
Xi'an Jiaotong University | XJTU · School of Aerospace

Ph.D.

About

56
Publications
12,281
Reads
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863
Citations
Additional affiliations
July 2016 - present
Xi'an Jiaotong University
Position
  • Professor – 教授
Description
  • School of Aerospace - 航天航空学院 State Key Laboratory for Strength and Vibration of Mechanical Structures - 机械结构强度与振动国家重点实验室
September 2015 - June 2016
Xi'an Jiaotong University
Position
  • Tenure-track PI – 特聘研究员
Description
  • School of Aerospace - 航天航空学院 State Key Laboratory for Strength and Vibration of Mechanical Structures - 机械结构强度与振动国家重点实验室
September 2013 - present
University of Twente
Position
  • PostDoc Position
Education
August 2009 - September 2013

Publications

Publications (56)
Article
Full-text available
The splashing of a drop impacting onto a liquid pool produces a range of different sized micro-droplets. At high impact velocities, the most significant source of these droplets is a thin liquid jet emerging at the start of the impact from the neck that connects the drop to the pool. We use ultra-high-speed video imaging in combination with high-re...
Article
Full-text available
When a drop impacts onto a liquid pool, it ejects a thin horizontal sheet of liquid, which emerges from the neck region connecting the two liquid masses. The leading section of this ejecta bends down to meet the pool liquid. When the sheet touches the pool, at an "elbow," it ruptures and sends off microdroplets by a slingshot mechanism, driven by s...
Article
Full-text available
When a drop impacts at low velocity onto a pool surface, a hemispheric air layer cushions and can delay direct contact. Herein we use ultra-high-speed video to study the rupture of this layer, to explain the resulting variety of observed distribution of bubbles. The size and distribution of micro-bubbles is determined by the number and location of...
Article
Full-text available
We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 μs aft...
Article
This study undertakes a numerical investigation of the dynamics of a finite-size air filament surrounded by a denser fluid medium with a range of viscosity. The two edges of the filament retract due to surface tension effects. It is shown that if the aspect ratio is small the filament recoil in a single bubble while for large aspect ratios the fila...
Article
A confined single air bubble rising near a vertical wall in a 2D Hele-Shaw cell was investigated experimentally with high-speed imaging. Wall effect was studied by varying the initial distance between the wall and the capillary needle to release the bubble, comparing to a confined-rising bubble without wall. The bubble of diameter of 3.65mm rises f...
Article
Full-text available
Small solid particles can be attached to an air–liquid interface due to the pulling of surface tension. We investigate experimentally under which conditions a spherical solid particle can be attached under a pendant drop, varying the density and diameter of the particle, as well as the size of the liquid drop. We demonstrate that depending on the d...
Preprint
Full-text available
Compound drop impacting on a solid surface is of considerable importance in industrial applications, such as combustion, food industry, and drug encapsulation. An intriguing phenomenon associated with this process is the occurrence of singular jets that are up to dozens of times faster than the impact velocity. These jets break into micro-droplets,...
Article
We study numerically the dynamics of an air-in-liquid compound drop impacting onto a solid surface. We demonstrate that the addition of a bubble in the drop decreases its maximum spreading. This decrease is explained by the lower kinetic energy of the drop, but also amplified by the formation of a vertical jet emerging from its center, and a relati...
Article
The splashing of liquid drops onto a solid surface is important for a wide range of applications, including combustion and spray coating. As the drop hits the solid surface, the liquid is ejected into a thin horizontal sheet expanding radially over the substrate. Above a critical impact velocity, the liquid sheet is forced to separate from the soli...
Article
We investigate numerically the contraction dynamics of a long air filament surrounded by liquid for a range of Ohnesorge numbers Oh. The contraction velocity rises to a maximum value Umax and then decreases due to the hydrodynamic drag force from the liquid medium. Umax follows a capillary-inertial scaling for low Oh while it shifts to a capillary-...
Article
Full-text available
Drop interaction with solid surfaces upon impact has been attracting a growing community of researchers who are focusing more and more on “complex” surfaces and “complex” drops. Recently, we are observing an emerging research trend related to the investigation of compound drop impact. Compound drops consist of two or more distinct continuous phases...
Article
A two-dimensional air sheet in a surrounding liquid contracts under surface tension. We investigate numerically and analytically this contraction dynamics for a range of Ohnesorge numbers $Oh$ . In a similar way as for liquid films, three contraction regimes can be identified based on the $Oh$ : vortex shedding, smooth contraction and viscous regim...
Article
When a drop falls and impacts on a liquid pool, it entraps an air disk below the drop, which then contracts into a central bubble. Here, we use high-speed imaging and high-resolution numerical simulations to characterize the air-disk contraction dynamics for different liquid properties. We show that the air disk can contract into a single central b...
Article
We study experimentally the dynamics of a liquid drop containing an air bubble falling onto a pool of the same liquid. We first develop a drop-on-demand setup capable of forming repeatable compound drops without any surfactant. Then, we investigate the impact dynamics above and below the pool surface combining two high-speed cameras. We identify th...
Article
Full-text available
Drop impact on solid surfaces is encountered in numerous natural and technological processes. Although the impact of single-phase drops has been widely explored, the impact of compound drops has received little attention. Here, we demonstrate a self-lubrication mechanism for water-in-oil compound drops impacting on a solid surface. Unexpectedly, th...
Article
Full-text available
We investigate the dynamics of a drop containing a single solid particle impacting on a solid surface. The particle rebounds through the drop during impact and can separate from the deposited liquid above an impact velocity threshold. We show that this threshold can be predicted by a simple energy balance. Moreover, we discover a new type of liquid...
Article
Full-text available
Cellulose nanofibril foams are cellulose-based porous materials with outstanding mechanical properties, resulting from the high strength-to-weight ratio of nanofibrils. Here we report the development of an optimized fabrication process for highly porous cellulose foams, based on a well-controlled freeze-thawing-drying (FTD) process at ambient press...
Article
Bioprinting has emerged as a powerful biofabrication technology with widespread applications in biomedical fields, due to its superiority in the high-throughput, high precision and 3D structure fabrication. For bioprinting, two of the most important parameters are the printing precision (i.e., droplets resolution) and structural fidelity (i.e., con...
Article
Full-text available
An experimental investigation of gas-liquid mass transfer in the wake of a confined air bubble sliding under an inclined wall in a 2D Hele-Shaw cell is reported. A colorimetric technique based on an oxygen-sensitive dye was used to visualize the oxygen transfer. Bubble velocities, shape eccentricities, interfacial areas and, for the first time, the...
Article
When a drop impacts on a liquid surface its bottom is deformed by lubrication pressure and it entraps a thin disc of air, thereby making contact along a ring at a finite distance from the centreline. The outer edge of this contact moves radially at high speed, governed by the impact velocity and bottom radius of the drop. Then at a certain radial l...
Article
Full-text available
For a limited set of impact conditions, a drop impacting onto a pool can entrap an air bubble as large as its own size. The subsequent rise and rupture of this large bubble plays an important role in aerosol formation and gas transport at the air-sea interface. The large bubble is formed when the impact crater closes up near the pool surface and is...
Article
Full-text available
The coalescence of drops is a fundamental process in the coarsening of emulsions. However, counter-intuitively, this coalescence process can produce a satellite, approximately half the size of the original drop, which is detrimental to the overall coarsening. This also occurs during the coalescence of bubbles, while the resulting satellite is much...
Article
Full-text available
Drops impacting at low velocities onto a pool surface can stretch out thin hemispherical sheets of air between the drop and the pool. These air sheets can remain intact until they reach submicron thicknesses, at which point they rupture to form a myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explo...
Article
Full-text available
One of the simplest splashing scenarios results from the impact of a single drop on a deep pool. The traditional understanding of this process is that the impact generates an axisymmetric sheet-like jet that later breaks up into secondary droplets. Recently it was shown that even this simplest of scenarios is more complicated than expected because...
Conference Paper
Full-text available
Droplets impacting on a pool of liquid and the subsequent bubble entrainment has been well studied for high Bond numbers where the droplets size is large and velocities are low. Here we study for the first time the droplet impact and bubble entrainment in an entirely new parameter regime (Bo ∼ 10^-2−10^-3, U ∼ 6-20 m/s, D ∼ 0.08-0.4 mm). We follow...
Conference Paper
Full-text available
A drop impacting on a pool of the same liquid can entrap air bubbles in many different ways. A peculiar entrapment was observed by Pumphrey and Elmore (1990) and remained unexplained until now. For a small range of parameters, the cavity produced by the impacting drop spreads radially in a dish-shape and then closes to entrap a bubble larger than t...
Conference Paper
Drops impacting at low velocities onto a pool surface can stretch out thin hemispheric sheets of air. These air sheets can remain intact until they reach submicron thicknesses, whereby they rupture to form myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In...
Conference Paper
Previous studies have shown that splashing is always expected above an impact velocity threshold for a liquid drop impacting on a solid surface1,2. We show here a surprising example where this behaviour can be modified by adding nanoparticles in the droplet. At low impact velocities, the droplet spreads on a smooth glass surface. By increasing the...
Conference Paper
Drop impact studies have a wide range of applications, many of which involve complex fluids. We study here the liquid drop impact of a silver nano-particles dispersion on a solid glass surface. This dispersion is used for inkjet printing of functional electronic materials. When the impact velocity increases, the drop classically splashes into small...
Article
Full-text available
When a drop impacts a pool of liquid it entraps a thin disk of air under its center. This disk contracts rapidly into a bubble to minimize surface energy. Herein we use ultra-high-speed imaging to measure the contraction speed of this disk when the drop and pool are of different liquids. For miscible liquids the contraction rate is governed by the...
Article
The picture on the cover is based on figure 8(d) of ‘Drop impact entrapment of bubble rings’, by M.-J. Thoraval, K. Takehara, T. G. Etoh & S. T. Thoroddsen.
Thesis
Full-text available
Drop impact is a canonical problem in fluid mechanics, with numerous applications in industrial as well as natural phenomena. The extremely simple initial configuration of the experiment can produce a very large variety of fast and complex dynamics. Scientific progress was made in parallel with major improvements in imaging and computational techno...
Conference Paper
Full-text available
We show how micro-bubble rings are entrapped under a drop impacting onto a pool surface. This fluid dynamics video is submitted to the APS DFD Gallery of Fluid Motion 2012, part of the 65th Annual Meeting of the American Physical Society's Division of Fluid Dynamics (18-20 November, San Diego, CA, USA).
Conference Paper
Full-text available
When a drop impacts at very low velocity onto a pool surface it is cushioned by a thin layer of air, which can be stretched into a hemispheric shape. We use ultra-high-speed video imaging to show how this thin air-layer ruptures. The number and locations of these ruptures determines the morphology of the resulting myriad of micro-bubbles. This flui...
Article
The picture on the cover is based on figure 1 of ‘Micro-bubble morphologies following drop impacts onto a pool surface’, by S. T. Thoroddsen, M.-J. Thoraval, K. Takehara & T. G. Etoh.
Conference Paper
We use ultra-high-speed video imaging, at frame-rates up to 1 million fps, to study the dynamics and breakup of both submicron sheets of liquid and submicron films of air. When a drop impacts onto a pool surface at sufficiently high impact velocity, it produces a fast-moving horizontal ejecta sheet, which emerges from the neck connecting the drop t...
Conference Paper
When a drop impacts a pool at very low velocities $V$, an air layer cushions the impact and prevents immediate contact. This air layer is stretched into a hemispheric shape and thins to a submicron thickness. We use silicone oils, where these films are more stable than for water [Saylor \& Bounds (2012), {\it AIChE J.}, online: {\it doi 10.1002/aic...
Conference Paper
Full-text available
We use ultra-high-speed imaging and numerical simulations (GERRIS, http://gfs.sf.net) to observe and analyze the formation of up to 14 air tori when a water drop impacts on a thin liquid film of water or other miscible liquids. They form during the early contact between the drop and the pool by the vertical oscillations of the ejecta sheet. They th...
Conference Paper
More than a century after the early work of Worthington, research on drop splash- ing is still very active, supported by the advances in high-speed imaging and numerical simulations. One of the main challenges is to understand the origin of the smallest droplets ejected during the impact1. High-speed imaging has recently uncovered the early emergen...
Conference Paper
We use ultra-high-speed video imaging to study the formation of micro-bubbles under a drop impacting onto a pool surface. When the drop impacts at low velocities, an air layer cushions the impact and prevents immediate contact with the pool. This air layer can stretch into a hemispheric shape which area can become larger than the drop surface, but...
Conference Paper
Full-text available
We studied experimentally and numerically the dynamics of the ejecta sheet produced by a drop impacting on a deep pool of the same liquid at high Reynolds and Weber numbers. Ultra-high speed imaging revealed a diversity of evolutions by using different mixtures of water and glycerine, and different impact velocities. We observed a transition from a...
Conference Paper
Drop impact on a liquid layer has fundamental industrial applications, as in fuel droplets impacting on the walls of a combustion chamber, spray painting, pesticide spraying, and ink-jet printing. Drop impact is also important for an understanding of natural mechanisms (e.g., aerosol formation through atomization and soil erosion by rain). Previous...
Conference Paper
At high Reynolds and Weber numbers, a drop impacting on a liquid layer produces a thin ejecta sheet between the drop and the pool. Ultra-high speed imaging reveals the complex ejecta shapes produced by the impact. We have characterized the evolution of the sheet for different viscosities (mixtures of water and glycerin) and impact velocities. It ap...

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