Nanoscale building blocks of many materials exhibit extraordinary mechanical properties due to their defect-free molecular structure. Translation these high macroscopic represents a difficult engineering challenge the necessity organize into multiscale patterns and mitigate defects emerging at larger scales. Cellulose nanofibrils (CNFs), most abundant structural element in living systems, has impressively strength stiffness, but natural or artificial cellulose composites are 3-15 times...

We describe, for the first time, an experiment devoted to study of spatial conformation a flexible fiber in turbulent flow. propose model transition from rigid regimes as intensity turbulence is increased or elastic energy decreased. This occurs typical length which observed experimentally and recovered by our analysis. also demonstrate that conformations fibers flow are analog polymers good solvent. last result opens some new creative ways distortions flows while addressing fundamental...

This paper presents an experimental study of different instability scenarios in a parallelogram-shaped internal wave attractor trapezoidal domain filled with uniformly stratified fluid. Energy is injected into the system via oscillatory motion vertical wall domain. Whole-field velocity measurements are performed conventional particle image velocimetry technique. In linear regime, total kinetic energy fluid used to quantify strength attractors as function coordinates parameter space defining...

We study the fragmentation of deformable and brittle fibers in inertial range turbulence using laboratory experiments numerical simulations. The process is shown to be limited at small scales by a physical cut-off length due fluid-structure interactions object with turbulence, thus independent fiber brittleness. This scenario, comprehensively modeled an evolution equation, leads accumulation fragments slightly longer than scale, as smaller are too short deformed broken turbulence. result may...

In the context of CO${}_{2}$ geological storage in deep saline aquifers, convective dissolution porous media has been subject theory and numerical studies at Darcy scale. By using both refractive index matching planar laser induced fluorescence, we measure onset characteristics (growth rate, wavelength, flux) instability a three-dimensional granular medium located below gas compartment. The obtained results show large discrepancies with theoretical predictions based on scale models but are...

In the present paper, we combine numerical and experimental approaches to study dynamics of stable unstable internal wave attractors. The problem is considered in a classic trapezoidal set-up filled with uniformly stratified fluid. Energy injected into system at global scale by small-amplitude motion vertical wall. Wave test tank measured help conventional synthetic schlieren particle image velocimetry techniques. closely reproduces one terms geometry operational range Reynolds Schmidt...

Flapping-based propulsive systems rely on fluid-structure interactions to produce thrust. At intermediate and high Reynolds numbers, vortex formation organization in the wake of such are crucial for generation a force. In this work, we experimentally investigate produced by tethered robotic fish immersed water tunnel. By systematically varying amplitude frequency tail as well free-stream speed, able observe characterize different streets function Strouhal number. The wakes three-dimensional...

Fishes, cetaceans, and many other aquatic vertebrates undulate their bodies to propel themselves through water. Swimming requires an intricate interplay between sensing the environment, making decisions, controlling internal dynamics, moving body in interaction with external medium. Within this sequence of actions initiating locomotion, biological physical laws manifest complex nonlinear effects, which do not prevent natural swimmers from demonstrating efficient movement. This raises two...

Prediction of glacier and polar ice sheet dynamics is a major challenge, especially in view changing climate. The flow behavior an mass fundamentally linked to processes at the grain subgrain scale. However, our understanding rheology microstructure evolution based on conventional deformation experiments, where samples are analyzed before after deformation, remains incomplete. To close this gap, we combine experiments with situ neutron diffraction textural analysis that allows continuous...

One of the pivotal questions in dynamics oceans is related to cascade mechanical energy abyss and its contribution mixing. Here, we propose internal-wave attractors large-amplitude regime as a unique self-consistent experimental numerical setup that models triadic interactions transferring from large-scale monochromatic input multi-scale motion. We also provide signatures discrete wave turbulence framework for internal waves. Finally, show how, beyond this regime, have clear transition...

Successful assembly of suspended nanoscale rod-like particles depends on fundamental phenomena controlling rotational and translational diffusion. Despite the significant developments in fluidic fabrication nanostructured materials, ability to quantify dynamics processing systems remains challenging. Here we demonstrate an experimental method for characterization orientation nanorod suspensions flows using relaxation. This relaxation, measured by birefringence obtained after rapidly stopping...

The reflection of internal gravity waves at sloping boundaries leads to focusing or defocusing. In closed domains, typically dominates and projects the wave energy onto 'wave attractors'. For small-amplitude waves, projection higher numbers by geometric can be balanced viscous dissipation high numbers. Contrary what was previously suggested, in interior shear layers may not sufficient explain experiments on attractors classical quasi-2D trapezoidal laboratory set-ups. Applying standard...

An interface between two miscible fluids is transient, existing as a non-equilibrium state before complete molecular mixing reached. However, during the existence of such an interface, which typically occurs at relatively short time scales, composition gradients boundary liquids cause stresses effectively mimicking interfacial tension. Here, we combine numerical modelling and experiments to study influence effective tension colloidal fibre dispersion its own solvent on flow in microfluidic...

The increased availability and brilliance of new X-ray facilities have in the recent years opened up possibility to characterize motion dispersed nanoparticles various microfluidic applications. One these applications is process making strong continuous filaments through hydrodynamic alignment assembly cellulose nanofibrils (CNF) demonstrated by H{\aa}kansson et al. [Nature communications 5, 2014]. In this it vital study flow, as turn affects final material properties dried filament. Small...

One of the important questions in dynamics oceans is related to cascade mechanical energy abyss and its contribution mixing. Here, we propose a unique self-consistent experimental numerical set up that models triadic interactions transferring from large-scale monochromatic input multi-scale internal wave motion. We show how this set-up can be used tackle open question studying turbulence laboratory, by providing, for first time, explicit evidence framework waves. Finally, beyond regime,...

Polydisperse fibre networks are the basis of many natural and man-made architectures, ranging from high-performance bio-based materials to components living cells tissues. The formation persistence such given by properties as length stiffness well number density fibre-fibre interactions. Studies network behavior, connectivity or rigidity thresholds, typically assume fixed isotropic orientation distributions, specifically for nanoscale fibres where methods providing time-resolved measurements...

Physical effects scale differently with size. As a necessary preliminary step toward geophysically significant extrapolations, an experimental and numerical study of the in internal wave attractors linear nonlinear regimes is made, showing two different scalings for beam width.

Nanocelluloses are seen as the basis of high-performance materials from renewable sources, enabling a bio-based sustainable future. Unsurprisingly, research has initially been focused on design new material concepts and less adapted fabrication processes that would allow large-scale industrial production widespread societal impact. In fact, even processing routes for making nanocelluloses understanding how mechanical action fibrillates plant raw materials, albeit chemically or enzymatically...

Dynamics of colloidal particles can be controlled by the application electric fields at micrometer–nanometer length scales. Here, an field-coupled microfluidic flow-focusing device is designed for investigating effect externally applied alternating current (AC) field on hydrodynamic assembly cellulose nanofibrils (CNFs). We first discuss how align parallel to direction without flow. Then, we apply during in channel and observe effects mechanical properties assembled nanostructures. further...

This paper revisits the problem of tidal conversion at a ridge in uniformly stratified fluid limited depth using measurements complex-valued added mass. When height sub-marine is non negligible with respect to water, can be enhanced supercritical regime or reduced subcritical large situation. Tidal even null for some specific cases. Here, we study experimentally influence finite on mass coefficients three diffierent shapes. We first show that low forcing frequency weakly by shallow...

Vertical soap films drain under the influence of gravity, as indicated by downward motion colorful horizontal interference fringes observed on their surfaces. In this study conducted with rectangular films, we experimentally characterize descent dynamics these isothickness and report its self-similar nature. We also show that result is equivalent to thickness profiles exhibiting a separation space time. By integrating new measurements data from literature across various conditions, validate...