Soft Matter and Complex Systems Seminar
sala 1.40, ul. Pasteura 5
2026-03-20 (09:30) 
Rafał Błaszkiewicz (IFT UW)
Unsteady Effects in Cilia-Mediated Transport and Microscale Mixing
Authors:
Rafał Błaszkiewicz¹, Margot Young², Albane Théry², Talia Becker Calazans², Arnold J.T.M. Mathijssen², Maciej Lisicki¹
¹University of Warsaw, Warsaw, Poland
²University of Pennsylvania, Philadelphia, USA
Cilia are key drivers of fluid transport in biological systems, from single-celled organisms to human tissues. Traditional models often treat ciliary flows as steady, yet the beating of cilia is inherently unsteady, generating flows that evolve on timescales comparable to viscous diffusion.
In this work, we use a time-dependent linear Stokes framework with Green’s functions and memory kernels to model flows generated by individual and coordinated cilia motion, represented by point-like “Pufflets.” Combining theory, simulations, and experiments, we examine how unsteady actuation affects particle trajectories and flow structures.
Our results show that unsteady effects can modify transport pathways and influence mixing at the microscale, particularly when multiple cilia interact. These findings highlight differences between steady and unsteady Stokes flows and provide insight into the mechanisms underlying cilia-mediated fluid transport.
The full study is available at: https://doi.org/10.48550/arXiv.2603.11020.
Rafał Błaszkiewicz¹, Margot Young², Albane Théry², Talia Becker Calazans², Arnold J.T.M. Mathijssen², Maciej Lisicki¹
¹University of Warsaw, Warsaw, Poland
²University of Pennsylvania, Philadelphia, USA
Cilia are key drivers of fluid transport in biological systems, from single-celled organisms to human tissues. Traditional models often treat ciliary flows as steady, yet the beating of cilia is inherently unsteady, generating flows that evolve on timescales comparable to viscous diffusion.
In this work, we use a time-dependent linear Stokes framework with Green’s functions and memory kernels to model flows generated by individual and coordinated cilia motion, represented by point-like “Pufflets.” Combining theory, simulations, and experiments, we examine how unsteady actuation affects particle trajectories and flow structures.
Our results show that unsteady effects can modify transport pathways and influence mixing at the microscale, particularly when multiple cilia interact. These findings highlight differences between steady and unsteady Stokes flows and provide insight into the mechanisms underlying cilia-mediated fluid transport.
The full study is available at: https://doi.org/10.48550/arXiv.2603.11020.