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Aquatic locomotion

About: Aquatic locomotion is a research topic. Over the lifetime, 69 publications have been published within this topic receiving 3796 citations. The topic is also known as: swim & active swimming.


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Journal ArticleDOI
TL;DR: In this paper, the authors used fluid-structure interaction modeling to determine possible enhancements in performance from shuffling different duty cycles together across multiple Reynolds numbers and contraction frequencies, and found that robust duty cycle combinations were determined that led to enhanced or impeded performance.
Abstract: Jellyfish (Medusozoa) have been deemed the most energy-efficient animals in the world. Their bell morphology and relatively simple nervous systems make them attractive to robotocists. Although, the science community has devoted much attention to understanding their swimming performance, there is still much to be learned about the jet propulsive locomotive gait displayed by prolate jellyfish. Traditionally, computational scientists have assumed uniform duty cycle kinematics when computationally modeling jellyfish locomotion. In this study we used fluid-structure interaction modeling to determine possible enhancements in performance from shuffling different duty cycles together across multiple Reynolds numbers and contraction frequencies. Increases in speed and reductions in cost of transport were observed as high as 80% and 50%, respectively. Generally, the net effects were greater for cases involving lower contraction frequencies. Overall, robust duty cycle combinations were determined that led to enhanced or impeded performance.
Book ChapterDOI
01 Jan 2021
TL;DR: Because sea otters rely almost exclusively on fur for thermal insulation, they groom (felt) their dense fur to trap an air layer next to the skin, and this essential behavior represents a significant part of the daily activity budget.
Abstract: Morphology and physiology enable but also constrain an animal’s behavior and physical performance, and sensory systems affect how an animal perceives its environment. Sea otters are grouped with other raptorial predators even though they capture and manipulate prey with their forepaws and consume it at the water’s surface. They have a short, robust skull and mandibles that enhance bite force. Their postcanine teeth have rounded or conical cusps and large surfaces for cracking or crushing mollusk shells, crustacean exoskeletons, or the test of echinoderms, such as sea urchins. The axial skeleton of sea otters is modified for aquatic locomotion, with a flexible spine and foreshortened limbs to reduce hydrodynamic drag. Forelimbs are used to capture and manipulate prey and for using tools (e.g., rocks) to open hard-shelled prey, but not for locomotion. Sea otters use dorsoventral undulation with simultaneous pelvic paddling during routine submerged swimming, and their hindfeet are modified into flippers for more efficient thrust. Because of their large lung volume, sea otters are positively buoyant and rest (sleep) effortlessly or swim in supine position at the surface, using alternate stroking of the hind flippers, although they are clumsy and slow when walking on land. To offset the high thermal conductivity of water, sea otters have a mass-specific basal metabolic rate that is 2.9-fold higher than a terrestrial eutherian mammal. As a result, they consume about 25% of their body mass daily, which requires them to spend 14–50% of their activity budget foraging. Because sea otters rely almost exclusively on fur for thermal insulation, they groom (felt) their dense fur to trap an air layer next to the skin, and this essential behavior represents a significant part of the daily activity budget. Sea otters have dichromatic color vision, underwater acuity similar to other marine mammals, and the aerial acuity of many terrestrial mammals. Although sea otters detect underwater sounds, hearing is primarily adapted for air, and they do not vocalize underwater. Their forepaws have good tactile surface discrimination for identifying prey by touch, but the role of their vibrissae in foraging is uncertain. Sea otters discriminate odorants and have a vomeronasal gland, which may detect pheromones that convey social or sexual (endocrine) cues that influence behavior and reproductive physiology. Based on the presence of taste buds, sea otters may have a gustatory sense. Compared to cetaceans, the sensory systems of sea otters are more similar to amphibious pinnipeds and terrestrial carnivorans.
Book ChapterDOI
01 Jan 2007
TL;DR: In this paper, a computational study on the unsteady hydrodynamics of pectoral fin locomotion of Rhinoptera Bonasus and Dasyatis Sabina is carried out and presented, which represent the undulatory and oscillatory locomotion, respectively.
Abstract: The mechanics of aquatic locomotion are of interest to biologists, dynamicists and engineers. Batoid fishes (skates and rays) propel themselves through the water primarily with their greatly expanded pectoral fins (pectoral-fin-based locomotion). Batoids exhibit two modes of pectoral swiminng behavior: (1) undulatory locomotion, termed ‘rajiform’, and (2) oscillatory locomotion, termed ‘mobuliform’. A computational study on the unsteady hydrodynamics of pectoral fin locomotion of Rhinoptera Bonasus and Dasyatis Sabina is carried out and presented, which represent the undulatory and oscillatory locomotion, respectively. Unsteady hydrodynamics around a pectoral fin is solved by a time-accurate solution of incompressible, laminar Navier-Stokes equations. Kinematic data of the pectoral fin locomotion used in the computational modeling are based on the experimental results. The pressure distribution of the pectoral fin was computed and integrated to give forces which were decomposed into lift and thrust. The velocity and vorticity field variation on the surface of pectoral fins and in the near-wake was computed throughout the swimming cycle. In the present study, we analyzed and compared the hydrodynamics and mechanmism of the Batoid pectoral fin locomotion between the two modes, and discovered how these patterns change with controllable factors, such as Renolds number, frequency, amplitude etc. The results show that forces on the fins of Rhinoptera Bonasus are much larger than that of Dasyatis Sabina. The load-bearing areas of Rhinoptera Bonasus are at the areas from the leading edge to the medial of the wing; while the load-bearing area of Dasyatis Sabina is the whole wavy fin. These characters are associated with the morphology of the wing skeleton. The propulsive mechanism of pectoral-fin-based locomotion is similar to that of the caudal-fin-based locomotion. A strong backward jet-stream in the wake contributes the net thrust, which is induced by the reversed von Karman vortex street. The effect of controllable factors on the hydrodynamics in Rhinoptera Bonasus swimming are similar to that in Dasyatis Sabina swimming.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20217
20201
20194
20183
20173
20166