title: Role of interfacial friction for flow instabilities in a thin polar-ordered active fluid layer.
abstract: We construct a generic coarse-grained dynamics of a thin inflexible planar layer of polar-ordered suspension of active particles that is frictionally coupled to an embedding isotropic passive fluid medium with a friction coefficient Γ. Being controlled by Γ, our model provides a unified framework to describe the long-wavelength behavior of a variety of thin polar-ordered systems, ranging from wet to dry active matter and free-standing active films. Investigations of the linear instabilities around a chosen orientationally ordered uniform reference state reveal generic moving and static instabilities in the system that can depend sensitively on Γ. Based on our results, we discuss estimation of bounds on Γ in experimentally accessible systems.
authors.affiliation: Condensed Matter Physics Division, Saha Institute of Nuclear Physics, Calcutta 700064, India.|Max-Planck Institut für Physik Komplexer Systeme, Nöthnitzer Str. 38, Dresden, D-01187 Germany.
authors.forename: Niladri
authors.initials: N
authors.lastname: Sarkar
authors.affiliation: Condensed Matter Physics Division, Saha Institute of Nuclear Physics, Calcutta 700064, India.|Max-Planck Institut für Physik Komplexer Systeme, Nöthnitzer Str. 38, Dresden, D-01187 Germany.
authors.forename: Abhik
authors.initials: A
authors.lastname: Basu