Dynamics and friction of a large colloidal particle in a bath of hard spheres: Langevin dynamics simulations and hydrodynamic description
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URI: http://hdl.handle.net/10835/15556
DOI: 10.1103/PhysRevE.101.052607
DOI: 10.1103/PhysRevE.101.052607
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Orts Gómez, Francisco José; Ortega López, Gloria; Martín Garzón, Gracia Ester; Fuchs, Matthias; Puertas López, Antonio ManuelFecha
2020-05-18Resumen
The analysis of the dynamics of tracer particles in a complex bath can provide valuable information about the microscopic behavior of the bath. In this work, we study the dynamics of a forced tracer in a colloidal bath by means of Langevin dynamics simulations and a theory model within continuum mechanics. In the simulations, the bath is comprised of quasihard spheres with a volume fraction of
50
%
immersed in a featureless quiescent solvent, and the tracer is pulled with a constant small force (within the linear regime). The theoretical analysis is based on the Navier-Stokes equation, where a term proportional to the velocity arises from coarse-graining the friction of the colloidal particles with the solvent. As a result, the final equation is similar to the Brinkman model, although the interpretation is different. A length scale appears in the model,
k
−
1
0
, where the transverse momentum transport crosses over to friction with the solvent. The effective friction coeffic...