English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The analysis of the dynamics of tracer particles in a complex bath canprovide valuable information about the microscopic behaviour of the bath. Inthis work, we study the dynamics of a forced tracer in a colloidal bath bymeans of Langevin dynamics simulations and a theory model within continuummechanics. In the simulations, the bath is comprised by quasi-hard spheres witha volume fraction of 50% immersed in a featureless quiescent solvent, and thetracer is pulled with a constant small force (within the linear regime). Thetheoretical analysis is based on the Navier Stokes equation, where a termproportional to the velocity arises from coarse-graining the friction of thecolloidal particles with the solvent. As a result, the final equation issimilar to the Brinkman model, although the interpretation is different. Alength scale appears in the model, 1/k_0, where the transverse momentumtransport crosses over to friction with the solvent. The effective frictioncoefficient experienced by the tracer grows with the tracer size faster thanthe prediction from Stokes law. Additionally, the velocity profiles in the bathdecay faster than in a Newtonian fluid. The comparison between simulations andtheory points to a boundary condition of effective partial slip at the tracersurface. We also study the fluctuations in the tracer position, showing that itreaches diffusion at long times, with a subdiffusive regime at intermediatetimes. The diffusion coefficient, obtained from the long-time slope of the meansquared displacement, fulfills the Stokes-Einstein relation with the frictioncoefficient calculated from the steady tracer velocity, confirming the validityof the linear response formalism.

Dynamics and friction of a large colloidal particle in a bath of hard spheres: Langevin dynamics simulations and hydrodynamic description