Red blood cells are modeled by an axisymmetric ellipsoid of fixed shape with internal circulation in shear flow without inertia. When accounting for membrane in-plane elasticity the model predicts the expected behaviors of flipping with orbit selection, rolling, frisbeeing, kayaking, and swinging.

Atomic Force Microscope observations find that two drops of radii 0.7 to 70 micrometers jump to contact when separated by a distance that scales as ($H{R}_{eq}/\gamma {)}^{1/3}$ for small drops and as $(H/\gamma {)}^{1/2}$ for larger drops.

Using Magnetic Resonance Velocimetry, we investigate the steady expiratory and the oscillatory flow in a planar double bifurcation model with geometric proportions relevant to the respiratory human airways for a range of Reynolds (Re) and Womersley (Wo) numbers.

A statistical analysis is conducted to provide support to a theoretical power-law scaling of the effect of differential molecular diffusion with respect to the Reynolds number in turbulent non-premixed combustion by using previously published direct number simulation data.

An exact analytic solution is derived for the dynamic response of a probe particle in a dilute colloidal suspension exposed to a strong step force.

The effect of inertia on the stability of viscoelastic flow is investigated. Three regions in the stability diagram are identified based on fluid elasticity, and a regime of flow relaminarization is discovered for high elasticity at Re up to 10, different from known turbulent drag reduction.

In channel flow hindered by two widely spaced obstacles, an elastic instability of the mixing layer arises near an inflection point on nonuniform shear velocity profiles, resulting in intermittent small vortices. In elastic turbulence a growth in the averaged vorticity above the transition is found.

Simulations predict that a pendulum immersed in an active fluid oscillates faster than in a passive fluid due to a reduction of the fluid inertia. The decrease in inertia is mediated by topological defects in the stress field, which can effectively decouple the bulk flow dynamics from the pendulum.

A liquid droplet spread on a solid substrate with nonuniform curvature, such as a conical surface, spontaneously moves. By assuming that the only source of dissipation is the contact line viscosity, we perturbatively determine the speed of the droplet and the total capillary force acting on it.

Shape deformation of a surfactant-laden droplet interacts uniquely with a given thermal field to alter its migration in the cross stream direction in response to an applied pressure gradient.

The optimization of the transport of suspended deformable particles in channels and networks is studied. The complexity of global optimization at the level of an entire network with channels of different lengths and diameters is highlighted, with a specific focus on blood circulation.

An experimental study of the rebounding dynamics of cavitation bubbles deformed by a free surface and by variable gravity is presented. It highlights the need to consider the rebound’s sensitivity to deformation when comparing experiments with theoretical models describing multiple bubble oscillations.

Shape-oscillating droplets rising in a liquid are simulated with insoluble surfactants adsorbed at their interface. Conditions are reported in which the average surface tension gradient induces a significant decrease of the rise velocity but does not impact the oscillation dynamics.

Experiments shows that with increasing sound intensity, an acoustically levitated drop buckles into a bowl shape and experiences a drastic expansion and closure, leading to the formation of an air bubble. This is attributed to the enhanced suction effect at the film rim due to the occurrence of resonance with sound field.

The electrophoretic mobility of a particle at the interface between two fluids is computed. For thin Debye layers, the Smoluchowki mobility is recovered. Generally, the mobility depends on the contact angle between the fluids and the particle. The interfacial deformation is also calculated.

The electrodeformation of a bio-vesicle suspended in liquid media depends on the conductivity ratio of fluid and vesicle, applied electric field, membrane capacitive charging, and vesicle initial shape. Our theoretical study provides important insights on this complex fluid-structure interaction.

The effect of the porosity and permeability on the wakes of porous rectangular cylinders is numerically studied using linear stability analyses. We show that the flow is progressively stabilized when obstacles of increased permeability are considered, up to the suppression of the vortex shedding.

Local stability equations are solved along closed fluid particle trajectories in the cylinder wake for Reynolds numbers in the range of 50 to 300. A bifurcation is shown to occur at $Re\approx 250$ and is argued to be related to the emergence of the well-known mode-B secondary instability.

We introduce an invasion-percolation model which reproduces quasistatic fluid-fluid displacement patterns in porous media under different wettability conditions. Depending on wettability, the fluid front advances through capillary invasion, cooperative filling, or corner flow.

A numerical investigation of retracting conical filaments with self-similar perturbations finds that for most cone angles, the perturbation amplitude must exceed a relatively large threshold for satellite drops to form. A static stability argument predicts this critical perturbation amplitude.

We perform drag force and particle tracking velocimetry measurements on a body-of-revolution coated with a superhydrophobic layer for $Re$ between $5\times {10}^5$ and $1.5\times {10}^6$. As $Re$ increases, drag reduction decreases, and a full plastron becomes isolated air bubbles as thin menisci.

An experimental study shows that splash formation is not reduced when spheres fall into water with a layer of soap bubbles on top. Instead, the bubble layer causes entrained air cavities to form at lower impact velocities. Results also show that the surfactant causes cavity formation to become radius dependent in cases where there is no bubble layer.

A plate floating on a cushion of air blown through a porous substrate is set in motion when herringbone-shaped grooves redirect the airflow in a preferred direction, allowing contactless manipulation of objects.

A flexible fiber settling in a viscous fluid deforms and reorients to adopt eventually a more or less pronounced “U” shape, regardless of its initial configuration. Three different regimes depending on the relative magnitude of gravitational and elastic forces are identified.

Oscillating microscale interfaces give rise not only to steady flows, but also steady inertial forces on particles. Our efficient theoretical description of these forces, which can be attractive or repulsive, provides a toolbox for separating and sorting microscale objects like biological cells.

An experimental study identifies four regimes of flow through complex microporous materials by measuring the velocity field at the pore scale. As Re is varied different pathways become effective at transporting fluid through the porous media, changing the effective permeability of the material.

When suspensions flow in microchannels or porous media, particles can get trapped and form clogs. A new model predicts the clogging dynamics and flow rate in simple porous media. The results are relevant to describe the aging of water filters and the influence of proppants on flow through rocks.

We find that the granular friction coefficient and other local quantities controlling the scaling behavior of sediment transport vary only little across all simulated transport conditions when evaluated at the interface between the solid-like granular bed and the gas-like transport layer.

Underwater turbidity currents erode and suspend granular material from underlying beds; the kinetics of this process controls overall flow dynamics. A study confirms a decades-old conjecture by Bagnold that the erosion process is driven by a balance between fluid and grain effects.

We further develop a two-range pseudopotential Lattice Boltzmann method for soft flowing systems using tunable surface tension and viscosity ratio. It is applicable to multicomponent fluids with a viscosity-independent disjoining pressure, a key to the microfluidic design of new porous materials.

In the early 1920s Sir G. I. Taylor derived a formula that can be fairly considered one of the cornerstones of large-scale tracer transport. Here, we extend Taylor’s formula to particles of any inertia including Basset and Faxèn corrections, plus other forces in the particle dynamics.

It is shown that there are an infinite number of invariants characterizing the large-scale structure in certain kinds of freely-decaying homogeneous turbulent velocity and passive scalar fields. A self-similarity assumption suggests that the large-scale anisotropy of the fields is persistent.

Approximate Bayesian Computation (ABC) is used to estimate unknown physical parameters in complex thermal-fluid flows.

The existence of large scale invariants in a Richtmyer-Meshkov turbulent mixing zone with a small Atwood number is studied. The impact of these invariants on the self-similarity of the flow, on its anisotropy and mixing levels, is then discussed.

A data assimilation technique called nudging is used to control the evolution of turbulence simulations. By studying the response of each simulation to the nudging, information on physical flow parameters is inferred from the data being assimilated.

A numerical simulation of freely decaying turbulence shows that the iconic curve of dimensionless dissipation against Reynolds number depends quite strongly on the choice of time at which the turbulence is assumed to have evolved from the arbitrary initial conditions.

Numerical simulations of the Gross-Pitaevskii equation reveal that parent and child vortices tend to be orthogonal to each other in quantum turbulence. This is a manifestation of the energy cascades and may be responsible for Kolmogorov’s law in superfluids.

Following the dimensional analysis approach of previous works, a law-of-the-wall is proposed for small-scale fluctuations in turbulent wall-flow. Experimental data shows that this universal scaling law extends across almost the entire wall-layer and exhibits a logarithmic trend in the outer region.

A model of normal-fluid dynamics and its coupling with superfluid vortices is formulated. The role of axial flow instabilities of superfluid vortices in energy transfer from normal-fluid to superfluid turbulence is indicated.

The analog of hydrodynamic helicity in superfluids is zero for all flows. A semiclassical limit is found in the link and writhe of bundles of superfluid vortices. Numerical simulations show that the dynamics of semiclassical helicity closely resemble those seen in experiments in viscous fluids.

With high-resolution 3D large Eddy Simulations we study internal solitary waves differently breaking over a sloping boundary. The entrainment parameter and mixing efficiency pry apart two effects of turbulent instabilities occurring in stratified fluid in terms of changes in bulk density profile.