Effect of aspect ratio in free-swimming plunging flexible plates

Yeh, Peter; Alexeev, Alexander

doi:10.1016/j.compfluid.2015.07.009

Cited by 40 publications

(29 citation statements)

References 48 publications

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“…Indeed, a commonly reported metric of solifuge chelicerae is their aspect ratio, with male chelicerae characterised by a greater length:width ratio than those of females ( Punzo, 1998a ; Peretti & Willemart, 2007 ). Whilst aspect ratio can itself be an important metric, often affecting function ( Kruyt et al, 2014 ; Yeh & Alexeev, 2016 ), the degree to which the ‘slender’ chelicerae of males are also dimorphic in total size is yet to be addressed in the literature. Calculations based on mean values presented by Punzo (1998a) do suggest female-biased dimorphism in cheliceral length and width, however.…”

Section: Introductionmentioning

confidence: 99%

Sexual dimorphism in the Arachnid orders

McLean

Garwood

Brassey

2018

PeerJ

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Sexual differences in size and shape are common across the animal kingdom. The study of sexual dimorphism (SD) can provide insight into the sexual- and natural-selection pressures experienced by males and females in different species. Arachnids are diverse, comprising over 100,000 species, and exhibit some of the more extreme forms of SD in the animal kingdom, with the males and females of some species differing dramatically in body shape and/or size. Despite this, research on arachnid SD has primarily focused on specific clades as opposed to observing traits across arachnid orders, the smallest of which have received comparatively little attention. This review provides an overview of the research to date on the trends and potential evolutionary drivers for SD and sexual size dimorphism (SSD) in individual arachnid orders, and across arachnids as a whole. The most common trends across Arachnida are female-biased SSD in total body size, male-biased SSD in relative leg length and SD in pedipalp length and shape. However, the evolution of sexually dimorphic traits within the group is difficult to elucidate due to uncertainty in arachnid phylogenetic relationships. Based on the dataset we have gathered here, we highlight gaps in our current understanding and suggest areas for future research.

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Section: Introductionmentioning

confidence: 99%

Sexual dimorphism in the Arachnid orders

McLean

Garwood

Brassey

2018

PeerJ

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“…Raspa et al [12] examined the role of aspect ratio in self-propelled undulatory plates. Yeh and Alexeev [13] studied the effect of the aspect-ratio in plunging flexible plates. All those studies found that the varying of aspect ratio will significantly change the propulsive performance and wake pattern.…”

Section: Introductionmentioning

confidence: 99%

Effects of Tail Geometries on the Performance and Wake Pattern in Flapping Propulsion

Dong

2016

Volume 1B, Symposia: Fluid Mechanics (Fundamental Issues and Perspectives; Industrial and Environmental Applications); Multipha

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Swimming fishes exhibit remarkable diversities of the caudal fin geometries. In this work, a computational study is conducted to investigate the effects of the caudal fin shape on the hydrodynamic performance and wake patterns in flapping propulsion. We construct the propulsor models in different shapes by digitizing the real caudal fins of fish across a wide range of species spanning homocercal tails with low aspect ratio (square shape used by bluegill sunfish, rainbow trout, etc.) or high aspect ratio (lunate shape adopted by tuna, swordfish, etc.), and even heterocercal caudal fin adopted by sharks. Those fin models perform the same flapping motion in a uniform flow to mimic fish’s forward swimming. We then simulate the flow around the flapping fins by an in-house immersed-boundary-method based flow solver. According to the analysis of the hydrodynamic performance, we have found that the lunate shape model (high aspect-ratio) always generates a larger thrust compared to other models. The comparison of the propulsive efficiency shows that the large aspect ratio fins (tuna and shark) have a higher efficiency when the Strouhal number (St) is in the range of steady swimming (0.2<St<0.4), while the lower aspect ratio caudal fins (catfish, trout, etc.) are more efficient when St>0.4, in which the fish is accelerating or maneuvering. Finally, the 3D wake patterns of those propulsors are analyzed in detail.

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“…The intrinsically unsteady mechanisms at play in such a problem have been widely studied and we refer the reader to other reviews [1,2,7,65]. Finite-size effects have also been shown recently to be essential to understand the relationship between thrust and drag in undulatory swimmers [64,66]. A clear example is the system of trailing stream-wise vortices produced at the edges of a self-propelled flexible foil (see fig.…”

Section: Vortex-induced Dragmentioning

confidence: 99%

“…As a model, we still consider a passive elastic body where the actuation is localized at one extremity as defined by equation (4.1). Practical examples of such systems have been investigated recently experimentally [51,88,90,92,[95][96][97] and numerically [66,86,89,98]. Equation (4.1) can be written in the weak amplitude approximation, except for the dissipation term, which holds due to the high transversal velocities involved along the body.…”

Section: Propagating Fish-like Kinematics Of a Passive Slender Elastimentioning

confidence: 99%

On the diverse roles of fluid dynamic drag in animal swimming and flying

Godoy-Diana¹,

Thiria²

2018

J. R. Soc. Interface.

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Questions of energy dissipation or friction appear immediately when addressing the problem of a body moving in a fluid. For the most simple problems, involving a constant steady propulsive force on the body, a straightforward relation can be established balancing this driving force with a skin friction or form drag, depending on the Reynolds number and body geometry. This elementary relation closes the full dynamical problem and sets, for instance, average cruising velocity or energy cost. In the case of finite-sized and time-deformable bodies though, such as flapping flyers or undulatory swimmers, the comprehension of driving/dissipation interactions is not straightforward. The intrinsic unsteadiness of the flapping and deforming animal bodies complicates the usual application of classical fluid dynamic forces balance. One of the complications is because the shape of the body is indeed changing in time, accelerating and decelerating perpetually, but also because the role of drag (more specifically the role of the local drag) has two different facets, contributing at the same time to global dissipation and to driving forces. This causes situations where a strong drag is not necessarily equivalent to inefficient systems. A lot of living systems are precisely using strong sources of drag to optimize their performance. In addition to revisiting classical results under the light of recent research on these questions, we discuss in this review the crucial role of drag from another point of view that concerns the fluid-structure interaction problem of animal locomotion. We consider, in particular, the dynamic subtleties brought by the quadratic drag that resists transverse motions of a flexible body or appendage performing complex kinematics, such as the phase dynamics of a flexible flapping wing, the propagative nature of the bending wave in undulatory swimmers, or the surprising relevance of drag-based resistive thrust in inertial swimmers.

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Effect of aspect ratio in free-swimming plunging flexible plates

Cited by 40 publications

References 48 publications

Sexual dimorphism in the Arachnid orders

Sexual dimorphism in the Arachnid orders

Effects of Tail Geometries on the Performance and Wake Pattern in Flapping Propulsion

On the diverse roles of fluid dynamic drag in animal swimming and flying

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