A mixture theory formulation for active suspensions

Abstract

We model an active suspension using the mixture theory. The suspension consists of a linear viscous liquid infused with multiple identical self‐propelled active particles. The primary focus of this study is to propose a continuum mechanical model for the partial stress tensor of the particle phase and the interaction forces between the fluid and particle phases. We examine a 1D shear flow that is driven by the active force of the particles and an external pressure gradient. Throughout this study, several physically interesting quantities are discussed, such as the volume fraction of the particle phase and the partial velocities of both phases. The numerical results show that, depending on the magnitude and direction of the active force and the pressure gradient, the particles can concentrate either in the center of the channel or along the wall.