Parts | Days | Selection | Search | Updates | Downloads | Help
BP: Fachverband Biologische Physik
BP 24: Poster B: Active Biological Matter, Cell Mechanics, Systems Biology, Computational Biophysics, etc.
BP 24.11: Poster
Tuesday, March 23, 2021, 16:00–18:30, BPp
Minimum Dissipation Theorem for Microswimmers — •Babak Nasouri1, Andrej Vilfan1,2, and Ramin Golestanian1,3 — 1Max Planck Institute for Dynamics and Self-Organization (MPIDS), Goettingen, Germany — 2J. Stefan Institute, Ljubljana, Slovenia — 3Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, United Kingdom
We derive a theorem for the lower bound on the energy dissipation rate by a rigid surface-driven active microswimmer of arbitrary shape in a fluid at a low Reynolds number. We show that, for any swimmer, the minimum dissipation at a given velocity can be expressed in terms of the resistance tensors of two passive bodies of the same shape with a no-slip and perfect-slip boundary. To achieve the absolute minimum dissipation, the optimal swimmer needs a surface velocity profile that corresponds to the flow around the perfect-slip body, and a propulsive force density that corresponds to the no-slip body. Using this theorem, we propose an alternative definition of the energetic efficiency of microswimmers that, unlike the commonly used Lighthill efficiency, can never exceed unity. We validate the theory by calculating the efficiency limits of spheroidal swimmers.