References of "Caps, Hervé"
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See detailInfluence of the gravity on the discharge of a silo
Dorbolo, Stéphane ULg; Maquet, Laurent ULg; Brandenbourger, Martin ULg et al

in Granular Matter (2013)

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See detailEffect of a capillary meniscus on the Faraday instability threshold
Caps, Hervé ULg; NGUYN THU LAM, Khanh Dang

in European Physical Journal E -- Soft Matter (2011), 34

Threshold for Faraday instability has been experimentally measured for slightly viscous liquids. Changing the size of the container containing the fluid allows us to emphasize the role played by the ... [more ▼]

Threshold for Faraday instability has been experimentally measured for slightly viscous liquids. Changing the size of the container containing the fluid allows us to emphasize the role played by the capillary meniscus on the onset for instability. As the container is getting smaller, an upset of the critical acceleration is observed. Below a given container diameter, eigen-modes are observed along the stability curve. A dissipation terms is proposed for considering the viscous dissipation against the walls of the container. [less ▲]

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See detailImpact of liquid droplets on granular media
Delon, Giles ULg; Terwagne, Denis ULg; Dorbolo, Stéphane ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2011)

Detailed reference viewed: 33 (7 ULg)
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See detailSingle thermal plume in locally heated vertical soap films
Adami, Nicolas ULg; Dorbolo, Stéphane ULg; Caps, Hervé ULg

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2011), 84

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See detailFaraday instability on a network
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

in Chaos (2010)

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See detailFrozen Splash
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

Poster (2010, November 21)

We have studied the splashing dynamics of water drops impacting granular layers. Depending on the drop kinetic energy, various shapes are observed for the resulting craters. Experimental parameters that ... [more ▼]

We have studied the splashing dynamics of water drops impacting granular layers. Depending on the drop kinetic energy, various shapes are observed for the resulting craters. Experimental parameters that have been considered are : the size of the millimetric droplets ; the height of the free fall, ranging from 1.5 cm to 100 cm ; and, the diam- eter of the grain. As the drop is impacting the sand layer, energy is dissipated and a splash of sand occurs. Meanwhile, surface tension, in- ertia and viscosity compete, leading to strong deformations of the drop which depend on the experimental conditions. Just after the drop en- ters into contact with the sand, imbibition takes place and increases the apparent viscosity of the fluid. The drop motion is stopped by this phenomenon. Images and fast-video recordings of the impact allowed to find scaling laws for the crater morphology and size. <br />This abstract is related to a fluid dynamics video for the APS DFD gallery of fluid motion 2010. [less ▲]

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See detailA fountain of droplets
Terwagne, Denis ULg; Delon, Giles ULg; Adami, Nicolas ULg et al

Poster (2010, November 21)

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges ... [more ▼]

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges of the immersed vessel generate surface waves that propagate towards the center of the bell. When the amplitude of the oscillation increases, wave amplitude increases. We study the influence of the angle between successive sides on the wave patterns. Two kinds of vessel have been studied: a triangular and a square prism. The shape of the air/oil meniscus depends on the angle between the sides of the considered prism. As the amplitude of the oscillation is increased, the triple line, which is the contact line between the solid and the air/oil interface, moves up and down. Above a given acceleration that depends on the immersion depth and on the shape vessel, wave goes under the corner edge of the bell. During the oscillation, the wave generates at the edges presents a singularity that leads eventually to a jet and a drop ejection. A drop is ejected at each oscillation. More complicated ejection can be produced with further increase of the amplitude. This is a sample arXiv article illustrating the use of fluid dynamics videos. [less ▲]

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See detailA fountain of droplets
Terwagne, Denis ULg; Delon, Giles ULg; Adami, Nicolas ULg et al

Poster (2010, November)

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges ... [more ▼]

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges of the immersed vessel generate surface waves that propagate towards the center of the bell. When the amplitude of the oscillation increases, wave amplitude increases. We study the influence of the angle between successive sides on the wave patterns. Two kinds of vessel have been studied: a triangular and a square prism. The shape of the air/oil meniscus depends on the angle between the sides of the considered prism. As the amplitude of the oscillation is increased, the triple line, which is the contact line between the solid and the air/oil interface, moves up and down. Above a given acceleration that depends on the immersion depth and on the shape vessel, wave goes under the corner edge of the bell. During the oscillation, the wave generates at the edges presents a singularity that leads eventually to a jet and a drop ejection. A drop is ejected at each oscillation. More complicated ejection can be produced with further increase of the amplitude. This is a sample arXiv article illustrating the use of fluid dynamics videos. [less ▲]

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See detailFaraday instability on a network
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

Poster (2010, March)

Detailed reference viewed: 20 (9 ULg)
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See detailBubble splitting in oscillatory flows on ground and in reduced gravity
Yoshikawa, Harunori; Zoueshtiagh, Farzam; Caps, Hervé ULg et al

in European Physical Journal E -- Soft Matter (2010), 31

The stability of centimeter scale air bubbles is studied in quiescent suspending liquid under an imposed oscillatory acceleration field. Experiments were performed in reduced- and normal-gravity ... [more ▼]

The stability of centimeter scale air bubbles is studied in quiescent suspending liquid under an imposed oscillatory acceleration field. Experiments were performed in reduced- and normal-gravity environments. A strong acceleration resulted in an instability leading to the breakups of the bubbles in both gravity environments. The breakup onset was investigated and found to be characterized by a critical acceleration acr . The influence of the liquid viscosity and the gravitational environment was studied. Empirical correlations for the onset are presented and discussed with the intention to reveal splitting mechanism. The inertial mechanism often deemed to cause the breakup of drops sub jected to a rapid gas stream is shown to give explanations consistent with the experiments. A breakup criterion for both gravitational environments is proposed through discussions from an energetic point of view. [less ▲]

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See detailAntibubbles, liquid onions and bouncing droplets
Vandewalle, Nicolas ULg; Terwagne, Denis ULg; Gilet, Tristan ULg et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2009), 344

Detailed reference viewed: 108 (18 ULg)
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See detailHybrid wetting state on micro-waffle textures
Caps, Hervé ULg; Vandormael, Denis; Loicq, Jerôme ULg et al

in Europhysics Letters (2009), 88

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See detailFoamability and structure analysis of foams in Hele-Shaw cell
Caps, Hervé ULg; Vandewalle, Nicolas ULg; Broze, Guy ULg et al

in Applied Physics Letters (2007), 90(21),

The authors have generated two-dimensional foams by imposing an intermittent drainage in a Hele-Shaw cell partially filled with a detergent/water mixture. The foam generation associated with this process ... [more ▼]

The authors have generated two-dimensional foams by imposing an intermittent drainage in a Hele-Shaw cell partially filled with a detergent/water mixture. The foam generation associated with this process is reproducible and depends on the surfactant molecules composing the solution. A kinetic model can be proposed for the foam evolution. The structure of the foam is also investigated: the average bubble side number and correlation functions are measured. Distinguishable behaviors are observed for different surfactant molecules. This way of producing a foam is thus adequate for applied foam structure characterizations and fundamental studies. (c) 2007 American Institute of Physics. [less ▲]

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See detailBubble rupture in a vibrated liquid under microgravity
Yoshikawa, Harunori; Zoueshtiagh, Farzam; Caps, Hervé ULg et al

in Microgravity Science and Technology (2007), 19

The response of an air bubble surrounded by a liquid in a sealed cell submitted to vibrations was investigated experimentally under microgravity conditions and compared to experiments under normal gravity ... [more ▼]

The response of an air bubble surrounded by a liquid in a sealed cell submitted to vibrations was investigated experimentally under microgravity conditions and compared to experiments under normal gravity conditions. As in normal gravity [1], it was observed that the bubble split into smaller parts when the acceleration of the vibrations reached a threshold. This threshold in microgravity is substantially smaller than that in normal gravity. Experimental results will be presented in terms of an acceleration based Bond number which has been found to characterize the bubble behaviour in the laboratory experiments [1]. Introduction [less ▲]

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See detailAir bubbles under vertical vibrations
Zoueshtiagh, F.; Caps, Hervé ULg; Legendre, M. et al

in European Physical Journal E -- Soft Matter (2006), 20(3), 317-325

This paper reports on an experimental study of the splitting instability of an air bubble a few centimetres in diameter placed in a sealed cylindrical cell filled with liquid and submitted to vertical ... [more ▼]

This paper reports on an experimental study of the splitting instability of an air bubble a few centimetres in diameter placed in a sealed cylindrical cell filled with liquid and submitted to vertical oscillations. The response of the bubble to the oscillations is observed with a high-speed video camera. It is found that the bubble dynamics is closely associated with the acceleration of the cell Gamma. For small acceleration values, the bubble undergoes minor shape deformations. With increasing acceleration values, these deformations are amplified and for sufficiently large Gamma the bubble becomes toroidal. The bubble may then become unstable and split into smaller parts. The onset of bubble division is studied and its dependency on physical parameters such as the fluid viscosity, the fluid surface tension and the initial size of the bubble is presented. It is found that the criterion for the bubble splitting process is associated with a threshold based on the acceleration of the oscillations. Above this threshold, the number of bubbles present in the cell is observed to grow until a final steady state is reached. Data analysis reveals that the final bubble size may be characterized in terms of Bond number. [less ▲]

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See detailFoaming dynamics in Hele-Shaw cells
Caps, Hervé ULg; Vandewalle, Nicolas ULg; Broze, Guy ULg

in Physical Review E (2006), 73(6, Pt 2), 65301

We have studied foaming dynamics in Hele-Shaw cells partially filled with a soap and water mixture. A series of upside-down flips produces an intermittent wetting of the cell and leads to foam formation ... [more ▼]

We have studied foaming dynamics in Hele-Shaw cells partially filled with a soap and water mixture. A series of upside-down flips produces an intermittent wetting of the cell and leads to foam formation. As a function of the number of flips, an increasing number of bubbles composes the foam, until saturation is observed. Statistical analysis shows that the bubble size follows a Gamma distribution. Contrary to common belief, this foaming dynamics by "shaking" creates homogeneous foam, even though the system may pass through transient heterogeneous configurations. A mechanistic interpretation is proposed and included into a theoretical model. [less ▲]

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See detailComparing the EthoVision 2.3 system and a new computerized multitracking prototype system to measure the swimming behavior in fry fish
Delcourt, Johann ULg; Becco, Christophe ULg; Ylieff, Marc ULg et al

in Behavior Research Methods (2006), 38

Coming from the framework of unmarked fry tracking, we compared the capacities, advantages, and disadvantages of two recent video tracking systems: EthoVision 2.3 and a new prototype of multitracking. The ... [more ▼]

Coming from the framework of unmarked fry tracking, we compared the capacities, advantages, and disadvantages of two recent video tracking systems: EthoVision 2.3 and a new prototype of multitracking. The EthoVision system has proved to be impressive for tracking a fry using the detection by gray scaling. Detection by subtraction has given less accurate results. Our video multitracking system is able to detect and track more than 100 unmarked fish by gray scaling technique. It permits an analysis at the group level as well as at the individual level. The multitracking program is able to attribute a number to each fish and to follow each one for the whole duration of the track. Our system permits the analysis of the movement of each individual, even if the trajectories of two fish cross each other. This is possible thanks to the theoretical estimation of the trajectory of each fish, which can be compared with the real trajectory (analysis with feedback). However, the period of the track is limited for our system (about 1 min), whereas EthoVision is able to track for numerous hours. In spite of these limitations, these two systems allow an almost continuous automatic sampling of the movement behaviors during the track. [less ▲]

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See detailCapillary rise in foams under microgravity
Caps, Hervé ULg; Cox, S. J.; Decauwer, H. et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2005), 261(1-mars Sp. Iss. SI), 131-134

The motion of liquid into a foam under low-gravity conditions is studied both experimentally and theoretically. The foam is confined to two dimensions in a Hele-Shaw cell and the liquid fraction measured ... [more ▼]

The motion of liquid into a foam under low-gravity conditions is studied both experimentally and theoretically. The foam is confined to two dimensions in a Hele-Shaw cell and the liquid fraction measured by image analysis. The foam imbibition is shown to be a diffusive process. Two models are analysed, corresponding to the limits of rigid and mobile interfaces in the Plateau borders. Liquid fraction profiles are compared to experimental ones. (c) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailBubble and granular flows: differences and similarities
Caps, Hervé ULg; Trabelsi, Samy ULg; Dorbolo, Stéphane ULg et al

in Physica A: Statistical Mechanics and its Applications (2004), 344(3-4), 424-430

We have experimentally studied the dense flow of identical bubbles below planes inclined at an angle theta. The flow is driven by the fast motion of dislocations. As a function of the density of ... [more ▼]

We have experimentally studied the dense flow of identical bubbles below planes inclined at an angle theta. The flow is driven by the fast motion of dislocations. As a function of the density of dislocations (controlled by the parameter theta), a transition occurs between a simple collective block motion and a granular-like surface flow regime. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 30 (6 ULg)