Print Email Facebook Twitter The role of sound propagation in concentrated colloidal suspensions Title The role of sound propagation in concentrated colloidal suspensions Author Bakker, A.F. Lowe, C.P. Faculty Applied Sciences Department Computational Physics Date 2002-04-01 Abstract In a suspension, the hydrodynamic interactions between particles can propagate by two mechanisms: relatively slowly, by the diffusion of transverse momentum, or relatively rapidly, by the propagation of sound waves. Here we describe computer simulation results for the collective and single particle dynamics of colloidal particles with the aim of clarifying the role of sound. We find that for single particle motion the effect is rather trivial. As for an isolated particle, compressibility modifies the decay of velocity fluctuations only at very short times. For collective correlations this is not true. Our results show that the multiple scattering of sound waves between particles can induce correlated collective motions on time scales comparable with the diffusion of transverse momentum. The effects of compressibility are no longer restricted to very short times and manifest themselves as rapid oscillations in the time dependence of the collective diffusion coefficient. We suggest that these oscillations can largely be explained in terms of “effective” incompressible hydrodynamic theory, the suspension bulk viscosity, kinematic viscosity, and speed of sound becoming the relevant parameters. The oscillations are furthermore centered on the (hypothetical) incompressible result. Thus, while the effects of sound propagation may extend to surprisingly long times, the net effect remains limited to very short times. We discuss where these sound-induced oscillations will be relevant experimentally. Subject colloidssuspensionshydrodynamicsacoustic wave propagationacoustic wave scatteringfluctuationscompressibilityviscosity To reference this document use: http://resolver.tudelft.nl/uuid:e89f4ec2-cd1e-44f9-a21a-7d5bb68aa4d8 DOI https://doi.org/10.1063/1.1454995 Publisher American Institute of Physics ISSN 0021-9606 Source http://link.aip.org/link/JCPSA6/v116/i13/p5867/s1 Source Journal of Chemical Physics, 116 (13), 2002 Part of collection Institutional Repository Document type journal article Rights (c) 2002 Bakker, A.F.; Lowe, C.P.; American Institute of Physics Files PDF Bakker_2002.pdf 136.69 KB Close viewer /islandora/object/uuid:e89f4ec2-cd1e-44f9-a21a-7d5bb68aa4d8/datastream/OBJ/view