The Richardson scaling law states that the mean square separation of a fluid particle pair grows according to t3 within inertial range and at intermediate times. theories predicting this regime assume is dispersion local, meaning only eddies scale contribute. These assumptions ignore structural organization turbulent flow into large-scale shear layers, where intense small-scale motions are boun...

Enstrophy, half the integral of the square of vorticity, plays a role in 2D turbulence theory analogous to that played by kinetic energy in the Kolmogorov theory of 3D turbulence. It is therefore interesting to obtain a description of the way enstrophy is dissipated at high Reynolds number. In this article we explore the notions of viscous and transport enstrophy defect, which model the spatial...

Polydisperse suspensions consist of small particles which are dispersed in a viscous fluid, and which belong to a finite number N of species that differ in size or density. Spatially one-dimensional kinematic models for the sedimentation of such mixtures are given by systems of N non-linear first-order conservation laws for the vector Φ of the N local solids volume fractions of each species. Th...

Recent mathematical results have shown that a central assumption in the theory of two-dimensional turbulence proposed by Batchelor (Phys. Fluids, vol. 12, 1969, p. 233) is false. That theory, which predicts a χ2/3k−1 enstrophy spectrum in the inertial range of freely-decaying turbulence, and which has evidently been successful in describing certain aspects of numerical simulations at high Reyno...

Effects of a multi-factorial falls prevention program for people with stroke returning home after rehabilitation: a randomized controlled trial. Batchelor FA, Hill KD, Mackintosh SF, Said CM, Whitehead CH. Arch. Phys. Med. Rehabil. 2012; ePub(ePub): ePub. Stroke victims aged 45 and older being discharged home received usual care (n = 85) which included referrals to physiotherapists and occupati...

[1] An improved understanding of the spatial distribution of diapycnal mixing in the oceans is the key to elucidating how meridional overturning circulation is closed. The challenge is to develop techniques which can be used to determine the variation of diapycnal mixing as a function of space and time throughout the oceanic volume. One promising approach exploits seismic reflection imaging of ...

Recently, a novel way of driving rapid microcentrifugation was discovered using ionic wind via ionization of the atmosphere around a singular electrode tip, driving liquid recirculation in a small cylindrical cavity due to interfacial shear. In the original work, the primary azimuthal surface recirculation was speculated to drive a secondary flow in the bulk of the liquid which resembles a heli...

The flow behavior inside the shrouded disk system is of importance in appropriate design of turbomachinery cavities and turbine test cell hydraulics dynamometer. The turbulent incompressible flow is analyzed for the shrouded disk system with axial clearance. The flow core behaves as a Batchelor type structure when a weak inflow is imposed on the disk cavity. By increasing the inflow, the centra...

This study investigates the settling behaviour of bidisperse colloidal silica suspensions in two different size ratios (100:500 nm and 500:800 nm) with various mixture volume fractions, using an analytical photocentrifuge. For dilute systems, translation rate profiles to distributions resulted more accurate measurements for both monodisperse systems than dynamic light scattering, comparison SEM...