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This work discusses a closed-loop control strategy for complex systems utilizing scarce and streaming data. A discrete embedding space is first built using hash functions applied to the sensor measurements from which a Markov process model…

Machine Learning · Statistics 2016-04-13 Florimond Guéniat , Lionel Mathelin , M. Yousuff Hussaini

We consider a model of two competing microswimming agents engaged in a pursue-evasion task within a low-Reynolds-number environment. Agents can only perform simple maneuvers and sense hydrodynamic disturbances, which provide ambiguous…

Fluid Dynamics · Physics 2022-03-04 Francesco Borra , Luca Biferale , Massimo Cencini , Antonio Celani

The geometric phase techniques for swimming in viscous flows express the net displacement of a swimmer as a path integral of a field in configuration space. This representation can be transformed into an area integral for simple swimmers…

Fluid Dynamics · Physics 2021-04-13 Lyndon Koens , Eric Lauga

Planktonic organisms, despite their passive drift in the ocean, exhibit complex responses to fluid flow, including escape behaviors and larval settlement detection. But what flow signals can they perceive? This paper addresses this question…

Fluid Dynamics · Physics 2024-11-27 Christophe Eloy

The net steady state flow pattern of a distorting sphere is studied in the framework of the bilinear theory of swimming at low Reynolds number. It is argued that the starting point of a theory of interacting active particles should be based…

Fluid Dynamics · Physics 2015-05-20 B. U. Felderhof

Hydrodynamic interactions are crucial for determining the cooperative behavior of microswimmers at low Reynolds numbers. Here we provide a comprehensive analysis of the scaling and strength of the interactions in the case of a pair of…

Soft Condensed Matter · Physics 2021-02-11 Sebastian Ziegler , Thomas Scheel , Maxime Hubert , Jens Harting , Ana-Sunčana Smith

Swimming at low Reynolds number in Newtonian fluids is only possible through non-reciprocal body deformations due to the kinematic reversibility of the Stokes equations. We consider here a model swimmer consisting of two linked spheres,…

Fluid Dynamics · Physics 2017-04-26 Babak Nasouri , Aditi Khot , Gwynn J. Elfring

Microswimmers in turbulent flows often navigate complex, heterogeneous, and obstacle-rich environments, where they exhibit intricate behaviors such as trapping at and escape from obstacles. We generalize recent $\mathcal{Q}-$learning…

Fluid Dynamics · Physics 2026-04-14 Vaishnavi Gajendragad , Akanksha Gupta , Nadia Bihari Padhan , Rahul Pandit

The role of passive body dynamics on the kinematics of swimming micro-organisms in complex fluids is investigated. Asymptotic analysis of small amplitude motions of a finite-length undulatory swimmer in a Stokes-Oldroyd-B fluid is used to…

Fluid Dynamics · Physics 2017-10-11 Becca Thomases , Robert D. Guy

Grasping, in both biological and engineered mechanisms, can be highly sensitive to the gripper and object morphology, as well as perception, and motion planning. Here we circumvent the need for feedback or precise planning by using an array…

Marine microorganisms must cope with complex flow patterns and even turbulence as they navigate the ocean. To survive they must avoid predation and find efficient energy sources. A major difficulty in analysing possible survival strategies…

Fluid Dynamics · Physics 2022-11-29 J. Qiu , N. Mousavi , K. Gustavsson , C. Xu , B. Mehlig , L. Zhao

The swimming of a spheroid immersed in a viscous fluid and performing surface deformations periodically in time is studied on the basis of Stokes equations of low Reynolds number hydrodynamics. The average over a period of time of the…

Fluid Dynamics · Physics 2016-11-23 B. U. Felderhof

Hiding an object in a chemical gradient requires to suppress the distortions it would naturally cause on it. To do so, we propose a strategy based on coating the object with a chemical reaction-diffusion network which can act as an active…

Chemical Physics · Physics 2020-07-01 Francesco Avanzini , Gianmaria Falasco , Massimiliano Esposito

Metachronal paddling is a swimming strategy in which an organism oscillates sets of adjacent limbs with a constant phase lag, propagating a metachronal wave through its limbs and propelling it forward. This limb coordination strategy is…

Fluid Dynamics · Physics 2025-07-28 Alana A. Bailey , Robert D. Guy

Self-propelled microparticles create flow fields that determine how they interact with surfaces, external flows, and each other. These flow fields fall into distinct classes--pushers, pullers, and neutral swimmers--each exhibiting…

Soft Condensed Matter · Physics 2025-12-25 Lisa Rohde , Gordei Anchutkin , Viktor Holubec , Frank Cichos

Mesoscopic active systems exhibit various unique behaviours - absent in passive systems - due to the forces generated by the corresponding constituents by converting their available free energies. However, estimating these forces - which…

Deep reinforcement learning has recently been applied to a variety of robotics applications, but learning locomotion for robots with unconventional configurations is still limited. Prior work has shown that, despite the simple modeling of…

Robotics · Computer Science 2023-01-31 Jiaheng Hu , Tony Dear

Self-propelled particles with hydrodynamic interactions (microswimmers) have previously been shown to produce long-range ordering phenomena. Many theoretical explanations for these collective phenomena are connected to instabilities in the…

Soft Condensed Matter · Physics 2017-05-03 Yuzhou Qian , Peter R. Kramer , Patrick T. Underhill

We study a generalized Navier-Stokes model describing the thin-film flows in non-dilute suspensions of ATP-driven microtubules or swimming bacteria that are enclosed by a moving ring-shaped container. Considering Stokes' second problem,…

Soft Condensed Matter · Physics 2018-10-31 Jonasz Słomka , Alex Townsend , Jörn Dunkel

We develop an adversarial-reinforcement learning scheme for microswimmers in statistically homogeneous and isotropic turbulent fluid flows, in both two (2D) and three dimensions (3D). We show that this scheme allows microswimmers to find…

Fluid Dynamics · Physics 2021-05-10 Jaya Kumar Alageshan , Akhilesh Kumar Verma , Jérémie Bec , Rahul Pandit