A portion of vulnerable stenosis can be deformed periodically under pulsatile blood flow condition. The deformable stenosis consists of fibrous cap covering lipid pool, which is analogous to a capsule containing oily liquid or soft gel. The deformation increases mechanical stress acting on the fibrous cap. The magnitude of the stress determines likelihood of rupture, which causes sudden cardiac death

Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using One-Dimensional Turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates

We present a statistical analysis of the behavior of the kinetic energy spectrum in the dissipative range of fully developed three-dimensional turbulence, This result also corroborates previous DNS studies which found that the spectrum in the near-dissipative range is best modeled by a stretched exponential with $

An impinging liquid jet impacts a target plate forming a hydraulic jump that can exhibit a steady polygonal geometry under a range of conditions. Experiments are conducted to determine the effect of weir geometry and flow history on mode selection and the geometry of these polygonal jumps. Modal transitions occur at different flow rates in upscale and downscale flow sweeps leading to hysteresis and

The steady motion and deformation of a lipid-bilayer vesicle translating through a circular tube in low Reynolds number pressure-driven flow are investigated numerically by means of axisymmetric boundary element method. This fluid-structure interaction problem is determined by three dimensionless parameters: reduced volume (a measure of the vesicle asphericity), geometric confinement (the ratio of

Energy transport in the spectral space is analyzed to study the mechanism underlying the Taylor–G"ortler-like (TGL) vortices that appear as two layers of streamwise-elongated roll cells in a turbulent channel flow subjected to fast streamwise system rotation. The transport equation of velocity-spectrum tensor in a rotating frame is derived to study the budget balance of energy spectra at different

We revisit the issue of Lagrangian irreversibility in the context of recent results [Xu, {et al.}, PNAS, 111, 7558 (2014)] on flight-crash events in turbulent flows and show how extreme events in the Eulerian dissipation statistics are related to the statistics of power-fluctuations for tracer-trajectories. Surprisingly, we find that particle trajectories in intense dissipation zones are dominated

We investigate experimentally the different shapes taken by a water drop freezing during its impact on a cold surface. We show that these shapes are formed by a water film that remains on top of the first formed ice layer. The capillary hydrodynamics of this water film dewetting on its own ice, coupled with its vertical solidification, is thus quantitatively characterized, allowing us to understand

A complete theory able to assess the longitudinal dispersion of a passive solute injected in an annular cavity subject to a pulsatile flow and a porous medium is provided. Aris-Taylor method of statistical moments is combined with the Brinkman approach for porous flows and morphological dispersion, in order to get an analytical relationship for the time-dependent enhanced dispersion coefficient. The

The presence of magnetic fields in many astrophysical objects is due to dynamo action, whereby a part of the kinetic energy is converted into magnetic energy. A turbulent dynamo that produces magnetic field structures on the same scale as the turbulent flow is known as the fluctuation dynamo. We use numerical simulations to explore the nonlinear, statistically steady state of the fluctuation dynamo

As pioneered by Donzis and Maqui ({J. Fluid Mech.}, vol. 797, 2016, pp. 181-200) and Khurshid and Donzis ({Phys. Fluids}, vol. 31, 2019, 015103), the compressible isotropic turbulence in thermal non-equilibrium is drawing attention in the fluid dynamics community. In the present study, the vibrational rate and the dissipation/production of vibrational energy fluctuation of compressible isotropic turbulence

The formation and evolution of micron-sized droplets of a Newtonian liquid generated on demand in an industrial inkjet printhead were studied experimentally and simulated numerically. The shapes and positions of droplets during droplet formation were observed using a high-speed camera and compared with their numerically obtained analogues. Both the experiments and the simulations use practical length

In many natural granular systems, the interstitial pores are filled with a fluid. Deformation of this two-phase system is complex, highly coupled, and depends on the initial and boundary conditions. Here we study granular compaction and fluid flow in a saturated, horizontally shaken, unconfined granular layer, where the fluid is free to flow in and out of the layer through the free upper surface during

We study experimentally the quasistatic displacement of an oil–air front across a localized constriction in a model open fracture. The front experiences capillary jumps at one end of the constriction in both imbibition and drainage, leading to a micro-scale pressure-saturation hysteresis cycle. At the other end the front is reversibly pinned. A condition of local mechanical equilibrium between the

Particles at a liquid interface can interact through capillarity, and depending on their size, shape or surface chemistry, it may lead to their aggregation. Yet, the two-dimensional structures thus created can be eroded by strong enough flows or as described in this paper via its own motion along a deformed interface. Here, we experimentally highlight an unexpectedly high resistance of such a granular

We report interpenetrating spiral vortices (ISV), a coexisting state of upward and downward propagating spiral/helical vortices, in a neutrally-buoyant suspension undergoing Taylor-Couette flow, with the inner cylinder rotating and the outer cylinder at rest. Along with ISV and Taylor vortex flow (TVF), the non-axisymmetric patterns, such as the wavy Taylor vortices (WTV) and spiral vortex flows (SVF)

Pleated membrane filters, which offer larger surface area to volume ratios than unpleated membrane filters, are used in a wide variety of applications. However, the performance of the pleated filter, as characterized by a flux-throughput plot, indicates that the equivalent unpleated filter provides better performance under the same pressure drop. Earlier work (Sanaei~& Cummings 2016) used a highly-simplified

The Navier-Stokes equations are greatly simplified when the Reynolds number, Re, tends to zero and inertial effects become negligible. A plethora of relevant, real-world flows occur at small but non-zero Re and these flows are generally well approximated by the simplified Stokes equations. However, the simplification to Stokes equations means important qualitative features that are inertial in origin

This work studies the aggregation of colloids under depletion attraction focusing on the effect of hydrodynamic interactions on cluster kinetics and average structures. Our numerical study is based on a variant of the immersed boundary method (inertial coupling method) which solves the solvent fluctuating hydrodynamics and instantaneously couple the particle and the fluid momentum transfer. Comparison

Past studies have shown that liquid jet breakup behavior can be classified into five regimes: Rayleigh, 1st wind, sinuous, 2nd wind, and atomization. By experimentally examining the breakup of superfluid and normal liquid 4He in an atmosphere of its own vapor we investigate the evolution of the jet behavior over a large range of the traditional three dimensional parameter space of the Ohnesorge and

Individual constituent balance equations are often used to derive expressions for species specific segregation velocities in flows of dense granular mixtures. We propose a semi-empirical expression for the interspecies momentum exchange in density bidisperse granular flows as an extension of ideas from kinetic theory and compare it to a previous viscous drag approach that is analogous to particles

We investigate the flow past circular, square and triangular cylinders embedded on spherical and cylindrical surfaces and quantify the effect of the embedding surface curvature on the flow characteristics. For the circular cylinder, we examine three Reynolds numbers Re = 40, 100, and 1000 based on cylinder diameter (D), and vary the normalized embedding surface curvature values D, where is the maximum

Understanding the behaviour of liquid phase turbulence near gas-liquid interfaces is of great interest in many fundamental, environmental, or industrial applications. For example, near-surface liquid side turbulence is known to enhance the mass transfers between the two phases. Descriptions of this behaviour for air-water systems exists in the literature, but the case of turbulence in a shear-thinning

We study the effect of spherical particles on the turbulent flow of a viscoelastic fluid and find that the drag reducing effect of polymer additives is completely lost for suspensions, with the drag increasing more than for suspensions in Newtonian fluids. This different behavior is due to three separate effects. First, the polymer stretching is reduced by the presence of the rigid particles, thus

Based on the lattice Boltzmann (LB) method, pore-scale simulations are performed to investigate the differential diffusion effects on the density-driven instability (DI) with chemical reaction A+B→C in {porous media. A partially miscible stratification is considered, and thus only solutes from the top fluid can diffuse down into the host fluid in pore spaces.} Tests with different values of the Rayleigh

We present a new technique to study preferential concentration of droplets in a turbulent air flow. Preferential concentration is the tendency of droplets to cluster in regions of strain, while avoiding regions of rotation. We study the properties of the droplet concentration field in zero mean flow turbulence that was created using an array of synthetic jets. The droplets are made of a phosphorescent

A study on the small-amplitude oscillation of a viscoelastic droplet suspended in a viscoelastic host liquid is carried out. The inner and outer liquids are assumed to be immiscible and their viscoelasticity is described by Jeffreys equation. The analytical characteristic equation is derived and the complex frequency is solved numerically. The effect of the outer host liquid on the oscillation of the