Journal ArticleDOI
Analysis of the Swimming of Microscopic Organisms
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TLDR
In this article, it was shown that if the waves down neighbouring tails are in phase, very much less energy is dissipated in the fluid between them than when the waves are in opposite phase.Abstract:
Large objects which propel themselves in air or water make use of inertia in the surrounding fluid. The propulsive organ pushes the fluid backwards, while the resistance of the body gives the fluid a forward momentum. The forward and backward momenta exactly balance, but the propulsive organ and the resistance can be thought about as acting separately. This conception cannot be transferred to problems of propulsion in microscopic bodies for which the stresses due to viscosity may be many thousands of times as great as those due to inertia. No case of self-propulsion in a viscous fluid due to purely viscous forces seems to have been discussed. The motion of a fluid near a sheet down which waves of lateral displacement are propagated is described. It is found that the sheet moves forwards at a rate 2π 2 b 2 /λ 2 times the velocity of propagation of the waves. Here b is the amplitude and λ the wave-length. This analysis seems to explain how a propulsive tail can move a body through a viscous fluid without relying on reaction due to inertia. The energy dissipation and stress in the tail are also calculated. The work is extended to explore the reaction between the tails of two neighbouring small organisms with propulsive tails. It is found that if the waves down neighbouring tails are in phase very much less energy is dissipated in the fluid between them than when the waves are in opposite phase. It is also found that when the phase of the wave in one tail lags behind that in the other there is a strong reaction, due to the viscous stress in the fluid between them, which tends to force the two wave trains into phase. It is in fact observed that the tails of spermatozoa wave in unison when they are close to one another and pointing the same way.read more
Citations
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Journal ArticleDOI
Engineering Nanorobots: Chronology of Modeling Flagellar Propulsion
TL;DR: In this paper, the authors present a review of existing theories in flagellar propulsion such as resistive force theory, slender body theory, Kirchhoff rod theory, bead model, and boundary element method as well as progress in designing the propulsion system of a nanorobot.
Dissertation
C. elegans locomotion : an integrated approach
TL;DR: An integrated neuromechancial model of C. elegans forward locomotion is applied, which demonstrates the ability to qualitatively and quantitatively account for locomotion across a range of media from water to agar, as well as in more complex (heterogeneous) environments.
Journal ArticleDOI
A 3-dimensional model of flagellar swimming in a Brinkman fluid
TL;DR: In this paper, the authors investigate 3D flagellar swimming in a fluid with a sparse network of stationary obstacles or fibers, where the Brinkman equation is used to model the average fluid flow where a flowdependent term, including a resistance parameter that is inversely proportional to the permeability, models the resistive effects of the fibers on the fluid.
Journal ArticleDOI
The Control and Optimization Design of the Fish-like Underwater Robot with the Aid of the Giant Magnetostrictive Material Actuator:
Xinsheng Xu,Faming Sun,G.P. Wang +2 more
TL;DR: In this article, the mechanism of the underwater fish-like robot, which is controlled by the giant magnetostrictive material actuator, is studied and a mechanical model of the robot is presented based on the relationship between the driving force and frequencies, which was controlled by external magnetic fields.
Journal ArticleDOI
Squirming in a viscous fluid enclosed by a Brinkman medium.
TL;DR: A minimal theoretical model is presented to investigate how heterogeneity created by a swimmer affects its own locomotion and reveals the existence of a minimum threshold size of mucus gel that a Swimmer needs to liquify in order to gain any enhancement in swimming speed.
References
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Journal ArticleDOI
Sea-urchin spermatozoa.
TL;DR: The head of the sea‐urchin spermatozoon is pear‐shaped and axially symmetrical, and the tail, which terminates in an axial fibre, probably contains spiral or coiled structures, as in mammalian spermatozoa.