Hydrodynamic Brownian motion and nanoscale transport efficiency in liquids
Abstract
Recent experiments have motivated a reexamination of Brownian motion, as hydrodynamic memory and colored thermal noise arising on short spatiotemporal scales lead to substantially different dynamical behavior. We revisit the problem of particle transport in liquids at low Reynolds number, where we account for the Basset-Boussinesq force and added mass effect induced by unsteady particle motion while reincorporating thermal fluctuations so as to satisfy fluctuation-dissipation. The resulting fluctuating Basset-Boussinesq-Oseen equation is solved numerically using an efficient method based on Markovian embedding, which can simultaneously capture the algebraic decay of the memory kernel and the colored noise spectrum to an arbitrary level of precision. We apply various driving forces to ensembles of submicron spherical particles in different liquids while holding constant the amount of input work; the resulting particle displacements and velocities are analyzed in terms of the magnitude, duration, and shape of different forcing protocols. For each protocol, we compute efficiencies for particle transport-with and without hydrodynamic effects-using the mean displacement and current density as proxies for output work. Implications for subcellular biology and nanofluidics are discussed.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MARS57005S