Efficiency of fish propulsion

Maertens, Audrey; Triantafyllou, Michael; Yue, Dick K. P.

doi:10.1088/1748-3190/10/4/046013

Cited by 100 publications

(77 citation statements)

References 48 publications

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“…In present study, the quasi-propulsive efficiency [20] is adopted to quantify the swimming efficiency. It is defined as the ratio of the power required to tow the fish body in a rigid and straight manner over the power used for self-propulsion with the same speed, which is given by:…”

Section: (4) 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: (4) 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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“…Although advances are being made in assessing the energetic costs and efficiency of swimming (e.g. Maertens et al, 2015), there are still few viable options for accurately calculating likely energetic expenditure at specific hydrodynamic locations.…”

Section: Introductionmentioning

confidence: 99%

Assessing hydrodynamic space use of brown trout, Salmo trutta, in a complex flow environment: a return to first principles.

Kerr

Manes

Kemp

2016

Journal of Experimental Biology

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It is commonly assumed that stream-dwelling fish should select positions where they can reduce energetic costs relative to benefits gained and enhance fitness. However, the selection of appropriate hydrodynamic metrics that predict space use is the subject of recent debate and a cause of controversy. This is for three reasons: (1) flow characteristics are often oversimplified, (2) confounding variables are not always controlled and (3) there is limited understanding of the explanatory mechanisms that underpin the biophysical interactions between fish and their hydrodynamic environment. This study investigated the space use of brown trout, Salmo trutta, in a complex hydrodynamic flow field created using an array of different sized vertically oriented cylinders in a large open-channel flume in which confounding variables were controlled. A hydrodynamic drag function (D) based on single-point time-averaged velocity statistics that incorporates the influence of turbulent fluctuations was used to infer the energetic cost of steady swimming. Novel hydrodynamic preference curves were developed and used to assess the appropriateness of D as a descriptor of space use compared with other commonly used metrics. Zones in which performanceenhancing swimming behaviours (e.g. Kaŕmań gaiting, entraining and bow riding) that enable fish to hold position while reducing energetic costs (termed 'specialised behaviours') were identified and occupancy was recorded. We demonstrate that energy conservation strategies play a key role in space use in an energetically taxing environment with the majority of trout groups choosing to frequently occupy areas in which specialised behaviours may be adopted or by selecting low-drag regions.

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“…Thrust and drag are both defined as the components of hydrodynamic force in the direction of swimming, the former along it, and the latter opposing it. For a self-propelling body—as a swimming shark is—separation between the two is essentially impossible [12]. In this study, we define drag as the respective component of the hydrodynamic force that would have acted on the shark if it were gliding stretched at the same speed and the same body angle.…”

mentioning

confidence: 99%

“…In this way, any possible variations in friction between the body and the water are accounted for by the propulsion efficiency. When swimming at high Reynolds numbers, these variations are expected to be small [12], and the propulsion efficiency is expected to be practically the same as the ideal efficiency [20,21]. …”

mentioning

confidence: 99%

Relations between morphology, buoyancy and energetics of requiem sharks

Iosilevskii

Papastamatiou

2016

R. Soc. open sci.

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Sharks have a distinctive shape that remained practically unchanged through hundreds of millions of years of evolution. Nonetheless, there are variations of this shape that vary between and within species. We attempt to explain these variations by examining the partial derivatives of the cost of transport of a generic shark with respect to buoyancy, span and chord of its pectoral fins, length, girth and body temperature. Our analysis predicts an intricate relation between these parameters, suggesting that ectothermic species residing in cooler temperatures must either have longer pectoral fins and/or be more buoyant in order to maintain swimming performance. It also suggests that, in general, the buoyancy must increase with size, and therefore, there must be ontogenetic changes within a species, with individuals getting more buoyant as they grow. Pelagic species seem to have near optimally sized fins (which minimize the cost of transport), but the majority of reef sharks could have reduced the cost of transport by increasing the size of their fins. The fact that they do not implies negative selection, probably owing to decreased manoeuvrability in confined spaces (e.g. foraging on a reef).

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Efficiency of fish propulsion

Cited by 100 publications

References 48 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

Assessing hydrodynamic space use of brown trout, Salmo trutta, in a complex flow environment: a return to first principles.

Relations between morphology, buoyancy and energetics of requiem sharks

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