PyStokes: phoresis and Stokesian hydrodynamics in Python

TL;DR

PyStokes is a Python library that efficiently simulates many-body hydrodynamic and phoretic interactions among spherical active particles, supporting complex boundary conditions and providing tools for analyzing suspension behavior.

Contribution

It introduces a modular, grid-free Python library for simulating many-body hydrodynamic and phoretic interactions with flexible boundary conditions, using spectral and Ritz-Galerkin methods.

Findings

Efficient computation of fluid flow and interactions in particle suspensions.

Supports confinement and boundary effects like walls and interfaces.

Demonstrated with six examples of active particle phenomena.

Abstract

We present a modular Python library for computing many-body hydrodynamic and phoretic interactions between spherical active particles in suspension, when these are given by solutions of the Stokes and Laplace equations. Underpinning the library is a grid-free methodology that combines dimensionality reduction, spectral expansion, and Ritz-Galerkin discretization, thereby reducing the computation to the solution of a linear system. The system can be solved analytically as a series expansion or numerically at a cost quadratic in the number of particles. Suspension-scale quantities like fluid flow, entropy production, and rheological response are obtained at a small additional cost. The library is agnostic to boundary conditions and includes, amongst others, confinement by plane walls or liquid-liquid interfaces. The use of the library is demonstrated with six fully coded examples simulating active phenomena of current experimental interest.