Regular Article - Flowing Matter
Pair dynamics of active force dipoles in an odd-viscous fluid
Max Planck Institute for Dynamics and Self-Organization (MPI DS), Am Faßberg 17, 37077, Göttingen, Germany
2 School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel
3 Wenzhou Institute, University of Chinese Academy of Sciences, 325001, Wenzhou, Zhejiang, China
4 Oujiang Laboratory, 325000, Wenzhou, Zhejiang, China
5 Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 192-0397, Tokyo, Japan
Accepted: 6 February 2023
Published online: 22 March 2023
We discuss the lateral dynamics of two active force dipoles, which interact with each other via hydrodynamic interactions in a thin fluid layer that is active and chiral. The fluid layer is modeled as a two-dimensional (2D) compressible fluid with an odd viscosity, while the force dipole (representing an active protein or enzyme) induces a dipolar flow. Taking into account the momentum decay in the 2D fluid, we obtain analytically the mobility tensor that depends on the odd viscosity and includes nonreciprocal hydrodynamic interactions. We find that the particle pair shows spiral behavior due to the transverse flow induced by the odd viscosity. When the magnitude of the odd viscosity is large as compared with the shear viscosity, two types of oscillatory behaviors are seen. One of them can be understood as arising from closed orbits in dynamical systems, and its circular trajectories are determined by the ratio between the magnitude of the odd viscosity and the force dipole. In addition, the phase diagrams of the particle dipolar angles are obtained numerically. Our findings reveal that the nonreciprocal response leads to complex dynamics of active particles embedded in an active fluid with odd viscosity.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.