LOW REYNOLDS NUMBER SWIMMING IN TWO DIMENSIONS

2000 ◽  
Author(s):  
ALEXANDRE CHERMAN ◽  
JOAQUíN DELGADO ◽  
FERNANDO DUDA ◽  
KURT EHLERS ◽  
JAIR KOILLER ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Two Dimensions ◽  
Low Reynolds Number Swimming ◽  
Low Reynolds

scholarly journals Low-Reynolds-number swimming at pycnoclines

2012 ◽  
Vol 109 (10) ◽  
pp. 3856-3861 ◽  
Author(s):  
A. Doostmohammadi ◽  
R. Stocker ◽  
A. M. Ardekani
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Low Reynolds Number Swimming ◽  
Low Reynolds

Optimal motion control of three-sphere based low-Reynolds number swimming microrobot

Robotica ◽  
2021 ◽  
pp. 1-17
Author(s):  
Hossein Nejat Pishkenari ◽  
Matin Mohebalhojeh
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Optimal Controller ◽  
Optimal Motion ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Three Sphere ◽  
Low Reynolds Number Swimming ◽  
Number Flow ◽  
Low Reynolds

Abstract Microrobots with their promising applications are attracting a lot of attention currently. A microrobot with a triangular mechanism was previously proposed by scientists to overcome the motion limitations in a low-Reynolds number flow; however, the control of this swimmer for performing desired manoeuvres has not been studied yet. Here, we have proposed some strategies for controlling its position. Considering the constraints on arm lengths, we proposed an optimal controller based on quadratic programming. The simulation results demonstrate that the proposed optimal controller can steer the microrobot along the desired trajectory as well as minimize fluctuations of the actuators length.

Microswimmer-induced chaotic mixing

2015 ◽  
Vol 779 ◽  
pp. 669-683 ◽  
Author(s):  
Mir Abbas Jalali ◽  
Atefeh Khoshnood ◽  
Mohammad-Reza Alam
Keyword(s):  
Reynolds Number ◽  
Periodic Orbits ◽  
Complex Geometry ◽  
Low Reynolds Number ◽  
Two Dimensions ◽  
Chaotic Advection ◽  
Entire Volume ◽  
Low Reynolds ◽  
The Stokes Equation ◽  
Linear Nature

Efficient mixing, typically characterised by chaotic advection, is hard to achieve in low Reynolds number conditions because of the linear nature of the Stokes equation that governs the motion. Here we show that low Reynolds number swimmers moving in quasi-periodic orbits can result in considerable stretching and folding of fluid elements. We accurately follow packets of tracers within the fluid domain and show that their trajectories become chaotic as the swimmer’s trajectory densely fills its invariant torus. The mixing process is demonstrated in two dimensions using the Quadroar swimmer that autonomously propels and tumbles along quasi-periodic orbits with multi-loop turning trajectories. We demonstrate and discuss that the streamlines of the flow induced by the Quadroar closely resemble the oscillatory flow field of the green alga Chlamydomonas reinhardtii. Our findings can thus be utilized to understand the interactions of microorganisms with their environments, and to design autonomous robotic mixers that can sweep and mix an entire volume of complex geometry containers.

scholarly journals Low-Reynolds-number flow past cylindrical bodies of arbitrary cross-sectional shape

1986 ◽  
Vol 164 ◽  
pp. 401-427 ◽  
Author(s):  
S. H. Lee ◽  
L. G. Leal
Keyword(s):  
Reynolds Number ◽  
Integral Equations ◽  
Low Reynolds Number ◽  
Uniform Flow ◽  
Two Dimensions ◽  
Cross Sectional ◽  
General Solutions ◽  
Flow Past ◽  
Low Reynolds ◽  
Sectional Shape

A numerical implementation of the method of matched asymptotic expansions is proposed to analyse two-dimensional uniform streaming flow at low Reynolds number past a straight cylinder (or cylinders) of arbitrary cross-sectional shape. General solutions for both the Stokes and Oseen equations in two dimensions are expressed in terms of a boundary distribution of fundamental single- and double-layer singularities. These general solutions are then converted to integral equations for the unknown distributions of singularity strengths by application of boundary conditions at the cylinder surface, and matching conditions between the Stokes and Oseen solutions. By solving these integral equations, using collocation methods familiar from three-dimensional application of ‘boundary integral’ methods for solutions of Stokes equation, we generate a uniformly valid approximation to the solution for the whole domain.We demonstrate the method by considering, as numerical examples, uniform flow past an elliptic cylinder, uniform flow past a cylinder of rectangular cross-section, and uniform flow past two parallel cylinders which may be either equal in radius, or of different sizes.

scholarly journals A two-dimensional model of low-Reynolds number swimming beneath a free surface

2011 ◽  
Vol 681 ◽  
pp. 24-47 ◽  
Author(s):  
DARREN CROWDY ◽  
SUNGYON LEE ◽  
OPHIR SAMSON ◽  
ERIC LAUGA ◽  
A. E. HOSOI
Keyword(s):  
Reynolds Number ◽  
Free Surface ◽  
Low Reynolds Number ◽  
Two Dimensional ◽  
Soft Interfaces ◽  
Low Reynolds Number Swimming ◽  
Variable Approach ◽  
Hydrodynamic Coupling ◽  
Low Reynolds ◽  
Mapping Techniques

Biological organisms swimming at low-Reynolds number are often influenced by the presence of rigid boundaries and soft interfaces. In this paper, we present an analysis of locomotion near a free surface with surface tension. Using a simplified two-dimensional singularity model and combining a complex variable approach with conformal mapping techniques, we demonstrate that the deformation of a free surface can be harnessed to produce steady locomotion parallel to the interface. The crucial physical ingredient lies in the nonlinear hydrodynamic coupling between the disturbance flow created by the swimmer and the free boundary problem at the fluid surface.

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