Flow control by means of a traveling curvature wave in fishlike escape responses

Li, Geng; Yu, Yinye; Tong, Bing‐Gang

doi:10.1103/physreve.84.056312

Cited by 25 publications

(24 citation statements)

References 28 publications

(31 reference statements)

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“…As a whole, when the travelling index is close to the optimal range, both the forward speed and the quasi-propulsive efficiency of carangiform fish reach the maximum values. In a manner similar to the flow past a wavy wall, however, the thrust of carangiform fish is reduced to the minimum due to the flow separation and the distribution of pressure [38][39][40]. …”

Section: Effects Of Travelling Index On Swimming Efficiencymentioning

confidence: 99%

CFD Studies of the Effects of Waveform on Swimming Performance of Carangiform Fish

Cui¹,

Gu²,

Li³

et al. 2017

Applied Sciences

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Carangiform fish, like mackerel, saithe and bass, swim forward by rhythmically passing body waves from the head to the tail. In this paper, the undulating motions are decomposed into the travelling part and the standing part by complex orthogonal decomposition (COD), and the ratio between these two parts, i.e., the travelling index, is proposed to analyse the waveform of fish-like movements. To further study the relative influences of the waveform on swimming performance, a self-propelled model of carangiform fish is developed by the level set/immersed boundary (LS-IB) method, and the in-house code is tested by two cases of flow past a sphere and an oscillating cylinder, respectively. In this study, the travelling index is varied in ranges up to 50% larger or smaller than the biological data. The results show that carangiform fish seem to favour a fast and efficient swimming motion with a travelling index of around 0.6. Meanwhile, we study several numerical cases with different amplitude coefficients (0.5~1.1) and tail-beat frequency (2 Hz~5 Hz), and then compare their swimming performance with each other. We found that the forward speed is closely related to the travelling index and tail-beat frequency, while the swimming efficiency is increased with the tail-beat frequency and amplitude coefficient. These results are also consistent with biological observations, and they might provide beneficial guidance with respect to the future design of robotic fish.

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Section: Effects Of Travelling Index On Swimming Efficiencymentioning

confidence: 99%

CFD Studies of the Effects of Waveform on Swimming Performance of Carangiform Fish

Cui¹,

Gu²,

Li³

et al. 2017

Applied Sciences

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“…Simulations of rectangular plate (AR=2, 30   , Re=300) was performed and compared to the published results of Taira and Colonius [26]. The wake structure of rectangular plate and time trace of lift and drag coefficients at large time are selected to compare.…”

Section: B Validationmentioning

confidence: 99%

“…TABLE I provides a concise summary of all the parameters involved and their range of variation. The computational domain size of all simulations was chosen as 30 for the larger aspect-ratio plate (AR=5.09). FIG.…”

Section: Fig 3 (A)mentioning

confidence: 99%

“…For instance, Techet [10] experimentally studied a robotic pitching-rolling foil with an NACA 0012 cross section and found that the high thrust and high propulsive efficiency of the foil could only be achieved when the foil flapped with a smaller maximum angle of attack ( max 30   ) and high Strouhal number (St=0.6). The high rolling amplitude did not appear to improve the thrust but could reduce the power losses.…”

Section: Introductionmentioning

confidence: 99%

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Quantification and Analysis of Propulsive Wake Topologies in Finite Aspect-Ratio Pitching-Rolling Plates

2016

46th AIAA Fluid Dynamics Conference

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Numerical simulations are used to investigate the effects of aspect-ratio (AR) on the wake topology and propulsive performance of flat-plates undergoing a pitching-rolling motion. Simulations are carried out using an in-house immersed-boundary-method-based direct numerical simulation (DNS) solver. A detailed analysis of the vortex formation shows that the general wake pattern of flapping plates shift from two branches of interconnected vortex loops for lower aspect-ratio cases (AR=1.27) to an integrated arc-shaped vortex structure for higher aspect-ratio cases (AR=5.09). The wake pattern changes also alter the instantaneous force production. The vortex shedding process of the lower aspect-ratio cases lead to two peaks in the lift and thrust force productions during each half cycle, and these two peaks gradually merge to a single peak as the aspect-ratio increasing. Simulations are also used to examine the propulsive performance of these plates over a range of Strouhal number.

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“…We should obtain them through a numerical method, which is to deal with the "self-propelled" swimming [12,13]. The values of the standard metabolic rate per unit mass P m /m and the muscle efficiency β may be found in previous literatures [11,14].…”

Section: Theoretical Formulation Of the Physical Problemmentioning

confidence: 99%

Optimal energy-utilization ratio for long-distance cruising of a model fish

Tong

2012

Phys. Rev. E

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The efficiency of total energy utilization and its optimization for long-distance migration of fish have attracted much attention in the past. This paper presents theoretical and computational research, clarifying the above well-known classic questions. Here, we specify the energy-utilization ratio (f(η)) as a scale of cruising efficiency, which consists of the swimming speed over the sum of the standard metabolic rate and the energy consumption rate of muscle activities per unit mass. Theoretical formulation of the function f(η) is made and it is shown that based on a basic dimensional analysis, the main dimensionless parameters for our simplified model are the Reynolds number (Re) and the dimensionless quantity of the standard metabolic rate per unit mass (R(pm)). The swimming speed and the hydrodynamic power output in various conditions can be computed by solving the coupled Navier-Stokes equations and the fish locomotion dynamic equations. Again, the energy consumption rate of muscle activities can be estimated by the quotient of dividing the hydrodynamic power by the muscle efficiency studied by previous researchers. The present results show the following: (1) When the value of f(η) attains a maximum, the dimensionless parameter R(pm) keeps almost constant for the same fish species in different sizes. (2) In the above cases, the tail beat period is an exponential function of the fish body length when cruising is optimal, e.g., the optimal tail beat period of Sockeye salmon is approximately proportional to the body length to the power of 0.78. Again, the larger fish's ability of long-distance cruising is more excellent than that of smaller fish. (3) The optimal swimming speed we obtained is consistent with previous researchers' estimations.

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Flow control by means of a traveling curvature wave in fishlike escape responses

Cited by 25 publications

References 28 publications

CFD Studies of the Effects of Waveform on Swimming Performance of Carangiform Fish

CFD Studies of the Effects of Waveform on Swimming Performance of Carangiform Fish

Quantification and Analysis of Propulsive Wake Topologies in Finite Aspect-Ratio Pitching-Rolling Plates

Optimal energy-utilization ratio for long-distance cruising of a model fish

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