Dispersion of ferrofluid aggregates in steady flows

Alicia M. Williams and Pavlos P. Vlachos

The authors present a study of ferrofluid aggregates interacting with a magnetically non-susceptible fluid in the presence of two different applied magnetic fields. Focused shadowgraphs of the interaction reveals three regimes of aggregate dynamics over the span of Reynolds numbers studied: stable, transitional, and shedding.

Phys. Fluids 23, 127102 (2011)

The relationship between the velocity skewness and the amplitude modulation of the small scale by the large scale in turbulent boundary layers

Romain Mathis, Ivan Marusic, Nicholas Hutchins, and K. R. Sreenivasan

In this study, the authors assess this apparent relationship and show that the Reynolds number trend in the skewness profile of u is strongly related to the amplitude modulation effect of the small scales by the large. This observation also leads to an alternative diagnostic for the amplitude modulation effect, which is one component of the skewness factor based on a scale decomposition.

Phys. Fluids 23, 121702 (2011)

Orientational order in concentrated suspensions of spherical microswimmers

Arthur A. Evans, Takuji Ishikawa, Takami Yamaguchi, and Eric Lauga

The authors use numerical simulations to probe the dynamics of concentrated suspensions of spherical microswimmers interacting hydrodynamically. Unlike previous work, it is shown that isotropic suspensions of spherical swimmers are also always unstable.

Phys. Fluids 23, 111702 (2011)

Rheology of binary granular mixtures in the dense flow regime

Anurag Tripathi and D. V. Khakhar

Results are presented for a single component system and binary mixtures with particles of different size and density. Inclination angles, composition, size ratios and density ratios are varied to obtain different segregated configurations at equilibrium.

Phys. Fluids 23, 113302 (2011)