Sylvain Joubaud

Sylvain Joubaud

École Normale Supérieure de Lyon
*This is an algorithmically generated author record based on publicly available information.
See Latest Publications
See Most Cited Publications
SciProfiles
ORCID Profile
Google Scholar

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Sylvain Joubaud has a total of 118 co-authors. Here are the top co-authors by number of shared publications:

Latest Publications

  • Website
    Google Scholar
    Open Access

    Emptying bottles filled with suspensions

    by Sasha Perez, Benjamin Monnet, Valérie Vidal, Sylvain Joubaud

    This work investigates, based on laboratory experiments, the influence of particles on the drainage of a bottle filled with an isodense suspension. Similarly to the drainage of a pure liquid, the flow rate remains constant during the whole emptying process and is primarily controlled by the size of the exit hole. Despite a hole-to-particle size ratio that would normally promote clogging, no such events are observed due to the periodic entrainment of air bubbles. The presence of particles causes a slight decrease in flow rate when increasing the particle initial packing fraction. Even for initial packing fractions of up to 60 %, it only decreases by at most 20 %. Revisiting the model of Clanet & Searby (2004) J. Fluid Mech . 510 , 145–168, the flow rate is found to be linked to the rise velocity of the bubbles, which is surprisingly nearly independent of the packing fraction, even for values as high as 60 %. This counterintuitive result suggests that the suspension becomes heterogeneous, with a particle-depleted region in the pathway of the bubbles. Moreover, during drainage, the suspension exiting the bottle has a smaller packing fraction than the initial suspension, leading to an accumulation of particles inside the bottle and therefore an increase in the global packing fraction inside the vessel. When this latter reaches a critical value close to random loose packing, particles start to emerge above the liquid free surface. Based on accurate measurements that enable the computation of the mean packing fraction at all times, a model is proposed to describe this transition.

    Cited by 1
  • Website
    Google Scholar

    Triadic instabilities of internal wave standing modes

    by Julie Deleuze, Ilias Sibgatullin, Philippe Odier, Sylvain Joubaud

  • Website
    Google Scholar
    Open Access

    Ice melting in saltwater: formation of a stratifiedsystem in laboratory experiments

    by Brivaël Collin, Louis-Alexandre Couston, Sylvain Joubaud, Romain Volk

    We report results on the melting of a tubular ice cuboid in saltwater heatedfrom below. We develop a meter-scale experimental setup capable of detectingthe ice-water interface and measuring the temperature, salinity, and velocity fields simultaneously, offering a route to quantitative understanding of multi-component systems with phase changes. We show that during melting, a two-layer system can form spontaneously due to the competition between the destabilizing temperature gradient and the stabilizing salinity gradient. The upper layer, closeto the ice, is quiescent while the lower layer is convective. Such a layered system displays a large vertical gradient of kinetic energy, which is characterized by means of a novel multi-step PIV approach that allows us to increase the signal-to-noise ratio in the velocity fields obtained by particle image velocimetry. Using a staircase profiling method, we enable reliable and non-intrusive temperature and salinity measurements. Using the measured salinity and temperature profiles of the two-layer system, we derive a model for the melting of ice which compares quantitatively well with experimental data.

  • Website
    Google Scholar
    • 15 September 2025
    • Published by HAL in HAL
    Open Access

    Ice melting in saltwater: formation of a stratified system in laboratory experiments

    by Brivaël Collin, Louis-Alexandre Couston, Sylvain Joubaud, Romain Volk

    We report results on the melting of a tubular ice cuboid in saltwater heated from below. We develop a meter-scale experimental setup capable of detecting the ice-water interface and measuring the temperature, salinity, and velocity fields simultaneously, offering a route to quantitative understanding of multicomponent systems with phase changes. We show that during melting, a two-layer system can form spontaneously due to the competition between the destabilizing temperature gradient and the stabilizing salinity gradient. The upper layer, close to the ice, is quiescent while the lower layer is convective. Such a layered system displays a large vertical gradient of kinetic energy, which is characterized by means of a novel multi-step PIV approach that allows us to increase the signalto-noise ratio in the velocity fields obtained by particle image velocimetry. Using a staircase profiling method, we enable reliable and non-intrusive temperature and salinity measurements. Using the measured salinity and temperature profiles of the two-layer system, we derive a model for the melting of ice which compares quantitatively well with experimental data.

  • Website
    Google Scholar
    Open Access

    Triad near-resonant instability of vertically bounded internal waves in non-uniform stratification

    by Akash Kav, Bruce R. Sutherland, Dheeraj Varma, Corentin Pacary, Sylvain Joubaud

    Vertically bounded, horizontally propagating internal waves may become unstable through triad resonant instability, in which two sibling waves in background noise draw energy from a parent internal tide. If the background stratification is uniform, then the condition for pure resonance between the parent and sibling wave frequencies and horizontal and vertical wavenumbers can be found semi-analytically from the roots of a polynomial expression. In non-uniform stratification, determining the frequencies and horizontal wavenumbers for which resonance occurs is less straightforward. We develop a theory for near-resonant excitation of a pair of sibling waves from a low-mode internal wave in which the proximity to pure resonance is characterised by the discrepancy between the forced sibling wave frequencies and the natural frequency of these modes. Knowing this discrepancy can be used methodically to determine pure resonance conditions. This inviscid theory is compared with numerical simulations of effectively inviscid waves. For comparison with laboratory experiments, the theory is adapted to include viscous effects both in the bulk of the fluid and at the side walls of the tank. We find that our theoretical predictions for frequencies and wavenumbers of the fastest growing sibling waves are generally consistent between theory, simulations and experiments, though theory overpredicts the growth rate observed in experiments. In all cases, the growth rate of sibling waves decreases with decreasing parent wave frequency, becoming negligibly small in experiments if the parent wave has frequency less than $\approx 0.7$ of the buoyancy frequency at the surface.

    Cited by 3
  • Website
    Google Scholar

    Axisymmetric internal wave tunneling

    by S. Boury, B. R. Sutherland, S. Joubaud, T. Peacock, P. Odier

    Cited by 1
  • Website
    Google Scholar

    Experimental study of superharmonic internal wave resonant triads in finite-depth nonuniform stratifications

    by Dheeraj Varma, Corentin Pacary, Thierry Dauxois, Sylvain Joubaud

    Cited by 4
  • Website
    Google Scholar
    Open Access

    Bubble dynamics in an inclined Hele-Shaw cell

    by Benjamin Monnet, J. John Soundar Jerome, Valérie Vidal, Sylvain Joubaud

    We report experimental results on the dynamics of large bubbles in a Hele-Shaw cell subject to various inclination angles with respect to gravity. Low Reynolds number cases are studied by injecting bubbles in an stagnant water/UCON mixture in three different Hele-Shaw cell geometry. The leading order rise speed $v_b$ follows the Taylor-Saffman limit which is inversely proportional to the viscosity $η$, but directly proportional to the square of the cell gap $h$ and the effective gravity, accounting for cell tilt angle $θ$. However, when the cell is inclined more and more, the bubble buoyancy in the cell gap leads to a substantial decrease in the rise speed, as compared to the Taylor-Saffman speed. Buoyancy pushes the bubble towards the top channel wall, whereby a difference between the lubrication film thickness on top of and underneath the rising bubble occurs. We attribute these observations to the loss of symmetry in the channel gap, due to cell inclination. Nonetheless, the top lubrication film is observed to follow the Bretherton scaling, namely, $(ηv_b/σ)^{2/3}$, where $σ$ is the liquid surface tension while the bottom film does not exhibit such a scaling. Finally, we illustrate that a model incorporating a friction term to the power balance between buoyancy and viscous dissipation matches well with all experimental data.

  • Website
    Google Scholar

    Bubble dynamics in an inclined Hele-Shaw cell

    by Benjamin Monnet, J. John Soundar Jerome, Valérie Vidal, Sylvain Joubaud

    We report experimental results on the dynamics of large bubbles in a Hele-Shaw cell subject to various inclination angles with respect to gravity. Low Reynolds number cases are studied by injecting bubbles in a stagnant water/UCON mixture in three different Hele-Shaw cell geometry. The leading order rise speed vb follows the Taylor-Saffman limit which is inversely proportional to the viscosity η, but directly proportional to the square of the cell gap h and the effective gravity, accounting for cell tilt angle θ. However, when the cell is increasingly inclined, the bubble buoyancy in the cell gap leads to a substantial decrease in the rise speed, as compared to the Taylor-Saffman speed. Buoyancy pushes the bubble toward the top channel wall, whereby a difference between the lubrication film thickness on top of and underneath the rising bubble occurs. We attribute these observations to the loss of symmetry in the channel gap, due to cell inclination. Nonetheless, the top lubrication film is observed to follow the Bretherton scaling, namely, (ηvb/σ)2/3, where σ is the liquid surface tension while the bottom film does not exhibit such a scaling. Finally, we illustrate that a model incorporating a friction term to the power balance between buoyancy and viscous dissipation matches well with all experimental data.

    Cited by 2
  • Website
    Google Scholar

    Observation of inertia-gravity wave attractors in an axisymmetric enclosed basin

    by Corentin Pacary, Thierry Dauxois, Evgeny Ermanyuk, Pascal Metz, Marc Moulin, Sylvain Joubaud

    Internal waves are ubiquitous in the ocean and play an essential role in the transport of energy and mixing. Their peculiar reflection enables the concentration of energy on a limit cycle. With wave beams viewed as rays, this reflection on an inclined slope shrinks its width and generically brings closer two initially different trajectories eventually reaching a limit cycle called an attractor. Following previous studies, a ray-tracing algorithm is used to track the convergence of wave beams onto such a structure in a 3D axisymmetric domain. This information is used to design experiments using a truncated conical shaped tank in order to form an inertia-gravity waves attractor in a 3D axisymmetric geometry. By increasing the amplitude of the forcing, an evolution of the attractor characteristics can be observed. The occurrence of waves at frequencies lower than the forcing frequency ω0 suggests triadic resonant instability in a rotating or in a stratified case. Experiments performed in a stratification-only or a rotation-only case indicate two distinct behaviors. The existence of easily excited standing waves, resonant modes of the tank, at frequencies lower than the forcing one enables sharp triadic resonance instability for internal gravity waves, which is not possible for inertial waves. The effect of the symmetry axis is also investigated by adding a cylinder of sufficient diameter at the center of the domain for the wave to reflect on and thereby avoid the interaction on the singularity. Without it, the large amplitude of the waves on the axis triggers nonlinear effects and mixing, denying the access to the wave turbulence regime.

    Cited by 12
Show all