title: Dynamics of a trapped Brownian particle in shear flows.
abstract: The Brownian motion of a particle in a harmonic potential, which is simultaneously exposed either to a linear shear flow or to a plane Poiseuille flow is investigated. In the shear plane of both flows the probability distribution of the particle becomes anisotropic and the dynamics is changed in a characteristic manner compared to a trapped particle in a quiescent fluid. The particle distribution takes either an elliptical or a parachute shape or a superposition of both depending on the mean particle position in the shear plane. Simultaneously, shear-induced cross-correlations between particle fluctuations along orthogonal directions in the shear plane are found. They are asymmetric in time. In Poiseuille flow thermal particle fluctuations perpendicular to the flow direction in the shear plane induce a shift of the particle's mean position away from the potential minimum. Two complementary methods are suggested to measure shear-induced cross-correlations between particle fluctuations along orthogonal directions.
authors.affiliation: Theoretische Physik I, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Holzer
authors.forename: Jochen
authors.initials: J
authors.lastname: Bammert
authors.forename: Roland
authors.initials: R
authors.lastname: Rzehak
authors.forename: Walter
authors.initials: W
authors.lastname: Zimmermann
mesh_terms: D007700:Kinetics; D016014:Linear Models; D055595:Mechanical Phenomena; D009038:Motion; D013269:Stochastic Processes; D013696:Temperature