TY - JOUR
T1 - Brownian dynamics of confined suspensions of active microrollers
AU - Balboa Usabiaga, Florencio
AU - Delmotte, Blaise
AU - Donev, Aleksandar
N1 - Funding Information:
We are grateful to Paul Chaikin and Michelle Driscoll for numerous discussions regarding the fingering instability in active roller suspensions, and to Edmond Chow for discussions of the Lanczos method. This work was supported in part by the National Science Foundation under Award No. DMS-1418706, and by the U.S. Department of Energy Office of Science, Office of Advanced Scientific Computing Research, Applied Mathematics program under Award No. DE-SC0008271. B. Delmotte was supported partially by the Materials Research Science and Engineering Center (MRSEC) program of the National Science Foundation under Award No. DMR-1420073. We thank the NVIDIA Academic Partnership program for providing GPU hardware for performing the simulations reported here.
Publisher Copyright:
© 2017 Author(s).
PY - 2017/4/7
Y1 - 2017/4/7
N2 - We develop efficient numerical methods for performing many-body Brownian dynamics simulations of a recently observed fingering instability in an active suspension of colloidal rollers sedimented above a wall [M. Driscoll, B. Delmotte, M. Youssef, S. Sacanna, A. Donev, and P. Chaikin, Nat. Phys. (2016), preprint arXiv:1609.08673. We present a stochastic Adams-Bashforth integrator for the equations of Brownian dynamics, which has the same cost but is more accurate than the widely used Euler-Maruyama scheme, and use a random finite difference to capture the stochastic drift proportional to the divergence of the configuration-dependent mobility matrix. We generate the Brownian increments using a Krylov method and show that for particles confined to remain in the vicinity of a no-slip wall by gravity or active flows, the number of iterations is independent of the number of particles. Our numerical experiments with active rollers show that the thermal fluctuations set the characteristic height of the colloids above the wall, both in the initial condition and the subsequent evolution dominated by active flows. The characteristic height in turn controls the time scale and wavelength for the development of the fingering instability.
AB - We develop efficient numerical methods for performing many-body Brownian dynamics simulations of a recently observed fingering instability in an active suspension of colloidal rollers sedimented above a wall [M. Driscoll, B. Delmotte, M. Youssef, S. Sacanna, A. Donev, and P. Chaikin, Nat. Phys. (2016), preprint arXiv:1609.08673. We present a stochastic Adams-Bashforth integrator for the equations of Brownian dynamics, which has the same cost but is more accurate than the widely used Euler-Maruyama scheme, and use a random finite difference to capture the stochastic drift proportional to the divergence of the configuration-dependent mobility matrix. We generate the Brownian increments using a Krylov method and show that for particles confined to remain in the vicinity of a no-slip wall by gravity or active flows, the number of iterations is independent of the number of particles. Our numerical experiments with active rollers show that the thermal fluctuations set the characteristic height of the colloids above the wall, both in the initial condition and the subsequent evolution dominated by active flows. The characteristic height in turn controls the time scale and wavelength for the development of the fingering instability.
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U2 - 10.1063/1.4979494
DO - 10.1063/1.4979494
M3 - Article
C2 - 28390356
AN - SCOPUS:85016733171
VL - 146
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 13
M1 - 134104
ER -