The dam-break problem for concentrated suspensions of neutrally buoyant particles

The dam-break problem for concentrated suspensions of neutrally buoyant particles

This paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our...

Turbulence attenuation by large neutrally buoyant particles

Instabilities in the dynamics of neutrally buoyant particles

The asymptotic dynamics of finite-size particles is governed by a slow manifold that is globally attracting for sufficiently small Stokes numbers. For neutrally buoyant particles suspensions , the slow dynamics coincide with that of infinitesimally small particles, therefore the suspension dynamics should synchronize with Lagrangian particle motions. Paradoxically, recent studies observe a scat...

Acceleration statistics of neutrally buoyant spherical particles in intense turbulence.

We measure acceleration statistics of neutrally buoyant spherical particles with a diameter 0.4 < d/eta < 27 in intense turbulence (400 < R(lambda) < 815). High speed cameras image polystyrene tracer particles in a flow between counterrotating disks. The measurements of acceleration variance clearly resolve the transition from the tracer like behavior of small particles to the much small...

Bailout embeddings and neutrally buoyant particles in three-dimensional flows.

We use the bailout embeddings of three-dimensional volume-preserving maps to study qualitatively the dynamics of small spherical neutrally buoyant impurities suspended in a time-periodic incompressible fluid flow. The accumulation of impurities in tubular vortical structures, the detachment of particles from fluid trajectories near hyperbolic invariant lines, and the formation of nontrivial thr...