The flow field and axial thrust generated by a rotating rigid helix at low Reynolds numbers

Zhong, Shan; Moored, Keith W.; Pinedo, Victor; Garcia-Gonzalez, Jesus; Smits, Alexander J.

doi:10.1016/j.expthermflusci.2012.10.019

Cited by 15 publications

(20 citation statements)

References 19 publications

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“…2b indicates the theoretically predicted exponential decay rate, e −2πr/λ , as the solid blue line [12]. This method is consistent with the computations of [5] and the experimental observations of [18] with rotating metal helices.…”

Section: Velocity Magnitude and Distance From The Wallsupporting

confidence: 80%

“…However, while there have been a number of experimental investigations into the induced fluid movement of bacterial flagella or carpets [10,7], artificial helices [18], and nematodes [16], to the authors' knowledge, there has been little theoretical investigations into the induced fluid flows, particularly at the intermediate scale of C. elegans, a 1mm long, unsegmented round worm.…”

Section: Introductionmentioning

confidence: 98%

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Modeling Fluid Flow Induced by C. elegans Swimming at Low Reynolds Number

Gutierrez

Sorenson

Strawbridge

2014

Theory and Practice of Natural Computing

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Abstract. C. elegans have been extensively researched regarding locomotion. However, most mathematical studies have focused on body dynamics rather than the fluid. As the nematodes undulate in a sinusoidal fashion, they cause fluid movement that has been studied experimentally but not modeled computationally on this scale. Utilizing the NavierStokes equation, regularized stokeslets, and the method of images, we computed the dynamics of the surrounding fluid. Our results strikingly matched experimental outcomes in various ways, including the distance particles travelled in one period of undulation, as well as qualitatively and quantitatively matching velocity fields. We then implemented this method using video data of swimming C. elegans and successfully reproduced the fluid dynamics. This is a novel application of the method of regularized stokeslets that combines theory and experiment. We expect this approach to provide insight in generating hypotheses and informing experimental design.

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Section: Velocity Magnitude and Distance From The Wallsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 98%

Modeling Fluid Flow Induced by C. elegans Swimming at Low Reynolds Number

Gutierrez

Sorenson

Strawbridge

2014

Theory and Practice of Natural Computing

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“…In Fig. 2(a), the axial component v z shows that the fluid is most strongly pumped in the interstitial volume of the helix, similar to the instantaneous axial flow field measured in experiments on a tethered rotating helix [51]. As the axial velocities of the helix beads are 0, v z must vanish at the helix surface.…”

Section: A Flow Field Generated By Rotating Helix In Sd Simulationssupporting

confidence: 63%

Biopolymer dynamics driven by helical flagella

et al. 2017

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Microbial flagellates typically inhabit complex suspensions of polymeric material which can impact the swimming speed of motile microbes, filter-feeding of sessile cells, and the generation of biofilms. There is currently a need to better understand how the fundamental dynamics of polymers near active cells or flagella impacts these various phenomena, in particular the hydrodynamic and steric influence of a rotating helical filament on suspended polymers. Our Stokesian dynamics simulations show that as a stationary rotating helix pumps fluid along its long axis, polymers migrate radially inwards while being elongated. We observe that the actuation of the helix tends to increase the probability of finding polymeric material within its pervaded volume. This accumulation of polymers within the vicinity of the helix is stronger for longer polymers. We further analyse the stochastic work performed by the helix on the polymers and show that this quantity is positive on average and increases with polymer contour length. Snapshots from a single simulation of a rotating helix and an advected polymer taken at times t0 < t1 < t2. A torque τ is distributed uniformly on the helix and, as it rotates, it generates a pumping flow. The polymer is drawn in radially and axially towards the helix, stretching in the process due to the induced shear flow. Once captured it winds around the helix and is pumped axially in the direction of the average flow.

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“…Two-dimensional (2D) particle image velocimetry (PIV) experiments have been primarily employed to study the swimmers with single helical flagellum [44,45]. Despite the progresses towards the understanding of bundle formation and disruption [46,47], the role of the bundled flagella configuration, such as phase difference in improvement of propulsive efficiency, attracted limited attention.…”

Section: Introductionmentioning

confidence: 99%

Thrust and Hydrodynamic Efficiency of the Bundled Flagella

et al. 2019

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The motility mechanism of prokaryotic organisms has inspired many untethered microswimmers that could potentially perform minimally invasive medical procedures in stagnant fluid regions inside the human body. Some of these microswimmers are inspired by bacteria with single or multiple helical flagella to propel efficiently and fast. For multiple flagella configurations, the direct measurement of thrust and hydrodynamic propulsion efficiency has been challenging due to the ambiguous mechanical coupling between the flow field and mechanical power input. To address this challenge and to compare alternative micropropulsion designs, a methodology based on volumetric velocity field acquisition is developed to acquire the key propulsive performance parameters from scaled-up swimmer prototypes. A digital particle image velocimetry (PIV) analysis protocol was implemented and experiments were conducted with the aid of computational fluid dynamics (CFD). First, this methodology was validated using a rotating single-flagellum similitude model. In addition to the standard PIV error assessment, validation studies included 2D vs. 3D PIV, axial vs. lateral PIV and simultaneously acquired direct thrust force measurement comparisons. Compatible with typical micropropulsion flow regimes, experiments were conducted both for very low and higher Reynolds (Re) number regimes (up to a Re number = 0.01) than that are reported in the literature. Finally, multiple flagella bundling configurations at 0°, 90° and 180° helical phase-shift angles were studied using scaled-up multiple concentric flagella thrust elements. Thrust generation was found to be maximal for the in-phase (0°) bundling configuration but with ~50% lower hydrodynamic efficiency than the single flagellum. The proposed measurement protocol and static thrust test-bench can be used for bio-inspired microscale propulsion methods, where direct thrust and efficiency measurement are required.

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The flow field and axial thrust generated by a rotating rigid helix at low Reynolds numbers

Cited by 15 publications

References 19 publications

Modeling Fluid Flow Induced by C. elegans Swimming at Low Reynolds Number

Modeling Fluid Flow Induced by C. elegans Swimming at Low Reynolds Number

Biopolymer dynamics driven by helical flagella

Thrust and Hydrodynamic Efficiency of the Bundled Flagella

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