title: Mesoscale simulation of phoretically osmotic boundary conditions.
abstract: Boundary walls can drive the tangential flow of fluids by phoretic osmosis when exposed to a gradient field, including chemical, thermal or electric potential gradient. At the microscale, such boundary driving mechanisms become quite pronounced. Here, we propose a mesoscale strategy to simulate the phoretically osmotic boundaries, in which the microscopic fluid-wall interactions are coarse-grained into the bounce-back or specular reflection, and the phoretically osmotic force is generated by selectively reversing the tangential velocity of specific fluid particles near the boundary wall. With this scheme, the phoretically osmotic boundary can be realized with a minimal modification to the widely used mesoscopic no-slip/slip hydrodynamic boundary condition. Its implementation is quite efficient and the resulting phoretically osmotic flow is flexibly tunable. Its validity is verified by performing extensive mesoscale simulations for both the diffusioosmotic and thermoosmotic boundaries. In particular, we use the proposed scheme to investigate fluid transport driven by the phoretic osmosis in microfluidic systems and the effects of the diffusioosmosis on the dynamics of active catalytic colloidal particles. Our work thus offers new possibilities to study the phoretically osmotic effect in active complex fluids and microfluidic systems by simulation, where the gradient fields are ubiquitous.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. mcyang@iphy.ac.cn lr@iphy.ac.cn fye@iphy.ac.cn kechen@iphy.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Mingcheng
authors.identifier: http://orcid.org/0000-0002-8742-9277
authors.initials: M
authors.lastname: Yang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. mcyang@iphy.ac.cn lr@iphy.ac.cn fye@iphy.ac.cn kechen@iphy.ac.cn.
authors.forename: Riu
authors.initials: R
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. mcyang@iphy.ac.cn lr@iphy.ac.cn fye@iphy.ac.cn kechen@iphy.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Fangfu
authors.initials: F
authors.lastname: Ye
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. mcyang@iphy.ac.cn lr@iphy.ac.cn fye@iphy.ac.cn kechen@iphy.ac.cn.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen