scholarly journals Three-dimensional kinematics and wake structure of the pectoral fins during locomotion in leopard sharks Triakis semifasciata

2000 ◽  
Vol 203 (15) ◽  
pp. 2261-2278 ◽  
Author(s):  
C.D. Wilga ◽  
G.V. Lauder
Keyword(s):  
Water Column ◽  
Three Dimensional ◽  
The Body ◽  
Force Balance ◽  
Body Tilt ◽  
Pectoral Fin ◽  
Body Angle ◽  
Pectoral Fins ◽  
Triakis Semifasciata ◽  
Leopard Sharks

The classical theory of locomotion in sharks proposes that shark pectoral fins are oriented to generate lift forces that balance the moment produced by the oscillating heterocercal tail. Accordingly, previous studies of shark locomotion have used fixed-wing aircraft as a model assuming that sharks have similar stability and control mechanisms. However, unlike airplanes, sharks are propelled by undulations of the body and tail and have considerable control of pectoral fin motion. In this paper, we use a new approach to examine the function of the pectoral fins of leopard sharks, Triakis semifasciata, during steady horizontal swimming at speeds of 0.5-2.0ls(−1), where l is total body length, and during vertical maneuvering (rising and sinking) in the water column. The planar orientation of the pectoral fin was measured using three-dimensional kinematics, while fluid flow in the wake of the pectoral fin and forces exerted on the water by the fin were quantified using digital particle image velocimetry (DPIV). Steady horizontal swimming in leopard sharks is characterized by continuous undulations of the body with a positive body tilt to the flow that decreases from a mean of 11 degrees to 0.6 degrees with increasing flow speeds from 0. 5 to 2.0ls(−1). Three-dimensional analysis showed that, during steady horizontal locomotion, the pectoral fins are cambered, concave downwards, at a negative angle of attack that we predict to generate no significant lift. Leopard shark pectoral fins are also oriented at a substantial negative dihedral angle that amplifies roll moments and hence promotes rapid changes in body position. Vortices shed from the trailing edge of the pectoral fin were detected only during vertical maneuvering. Starting vortices are produced when the posterior plane of the pectoral fin is actively flipped upwards or downwards to initiate rising or sinking, respectively, in the water column. The starting vortex produced by the pectoral fin induces a pitching moment that reorients the body relative to the flow. Body and pectoral fin surface angle are altered significantly when leopard sharks change vertical position in the water column. Thus, locomotion in leopard sharks is not analogous to flight in fixed-wing aircraft. Instead, a new force balance for swimming leopard sharks is proposed for steady swimming and maneuvering. Total force balance on the body is adjusted by altering the body angle during steady swimming as well as during vertical maneuvering, while the pectoral fins appear to be critical for initiating maneuvering behaviors, but not for lift production during steady horizontal locomotion.

scholarly journals Locomotion in sturgeon: function of the pectoral fins

1999 ◽  
Vol 202 (18) ◽  
pp. 2413-2432 ◽  
Author(s):  
C.D. Wilga ◽  
G.V. Lauder
Keyword(s):  
Water Column ◽  
Three Dimensional ◽  
Total Body Length ◽  
The Body ◽  
Force Balance ◽  
Propulsive Force ◽  
Pectoral Fin ◽  
Posterior Portion ◽  
Body Angle ◽  
Pectoral Fins

Pectoral fins are one of the major features of locomotor design in ray-finned fishes and exhibit a well-documented phylogenetic transition from basal to derived clades. In percomorph fishes, the pectoral fins are often used to generate propulsive force via oscillatory movements, and pectoral fin propulsion in this relatively derived clade has been analyzed extensively. However, in the plesiomorphic pectoral fin condition, exemplified by sturgeon, pectoral fins extend laterally from the body in a generally horizontal orientation, have been assumed to generate lift to balance lift forces and moments produced by the heterocercal tail, and are not oscillated to generate propulsive force. The proposal that pectoral fins in fishes such as sturgeon generate lift during horizontal locomotion has never been tested experimentally in freely swimming fishes. In this paper, we examine the function of pectoral fins in sturgeon swimming at speeds from 0.5-3.0 L s(−)(1), where L is total body length. Sturgeon were studied during steady horizontal locomotion as well as while sinking and rising in the water column. Pectoral fin function was quantified using three-dimensional kinematics to measure the orientation of the fin surface, digital particle image velocimetry (DPIV) was used to describe flow in the wake of the fin and to estimate force exerted on the water, and electromyography was used to assess pectoral fin muscle function. Sturgeon (size range 25–32 cm total length) swam horizontally using continuous undulations of the body with a positive body angle that decreased from a mean of 20 degrees at 0.5 L s(−)(1) to 0 degrees at 3.0 L s(−)(1). Both the angle of the body and the pectoral fin surface angle changed significantly when sturgeon moved vertically in the water column. Three-dimensional kinematic analysis showed that during steady horizontal swimming the pectoral fins are oriented with a negative angle of attack predicted to generate no significant lift. This result was confirmed by DPIV analysis of the pectoral fin wake, which only revealed fin vortices, and hence force generation, during maneuvering. The orientation of the pectoral fins estimated by a two-dimensional analysis alone is greatly in error and may have contributed to previous suggestions that the pectoral fins are oriented to generate lift. Combined electromyographic and kinematic data showed that the posterior half of the pectoral fin is actively moved as a flap to reorient the head and body to initiate rising and sinking movements. A new force balance for swimming sturgeon is proposed for steady swimming and vertical maneuvering. During steady locomotion, the pectoral fins generate no lift and the positive body angle to the flow is used both to generate lift and to balance moments around the center of mass. To initiate rising or sinking, the posterior portion of the pectoral fins is actively moved ventrally or dorsally, respectively, initiating a starting vortex that, in turn, induces a pitching moment reorienting the body in the flow. Adjustments to body angle initiated by the pectoral fins serve as the primary means by which moments are balanced.

Fluid dynamics of flapping aquatic flight in the bird wrasse:three-dimensional unsteady computations with fin deformation

2002 ◽  
Vol 205 (19) ◽  
pp. 2997-3008 ◽  
Author(s):  
Ravi Ramamurti ◽  
William C. Sandberg ◽  
Rainald Löhner ◽  
Jeffrey A. Walker ◽  
Mark W. Westneat
Keyword(s):  
Fluid Dynamics ◽  
Steady State ◽  
Three Dimensional ◽  
Force Production ◽  
Time History ◽  
The Body ◽  
Vertical Acceleration ◽  
Field Variation ◽  
Pectoral Fin ◽  
Pectoral Fins

SUMMARY Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists,biomechanics researchers and engineers. In the present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin,and previously measured fin kinematics, as the starting points for computational investigation of three-dimensional (3-D) unsteady fluid dynamics. We performed a 3-D steady computation and a complete set of 3-D quasisteady computations for a range of pectoral fin positions and surface velocities. An unstructured, grid-based, unsteady Navier—Stokes solver with automatic adaptive remeshing was then used to compute the unsteady flow about the wrasse through several complete cycles of pectoral fin oscillation. The shape deformation of the pectoral fin throughout the oscillation was taken from the experimental kinematics. The pressure distribution on the body of the bird wrasse and its pectoral fins was computed and integrated to give body and fin forces which were decomposed into lift and thrust. The velocity field variation on the surface of the wrasse body, on the pectoral fins and in the near-wake was computed throughout the swimming cycle. We compared our computational results for the steady, quasi-steady and unsteady cases with the experimental data on axial and vertical acceleration obtained from the pectoral fin kinematics experiments. These comparisons show that steady state computations are incapable of describing the fluid dynamics of flapping fins. Quasi-steady state computations, with correct incorporation of the experimental kinematics, are useful when determining trends in force production, but do not provide accurate estimates of the magnitudes of the forces produced. By contrast, unsteady computations about the deforming pectoral fins using experimentally measured fin kinematics were found to give excellent agreement, both in the time history of force production throughout the flapping strokes and in the magnitudes of the generated forces.

Quebecius quebecensis (Whiteaves), a porolepiform crossopterygian (Pisces) from the Late Devonian of Quebec, Canada

1987 ◽  
Vol 24 (12) ◽  
pp. 2351-2361 ◽  
Author(s):  
Hans-Peter Schultze ◽  
Marius Arsenault
Keyword(s):  
Ventral Side ◽  
The Body ◽  
Late Devonian ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Median Fins ◽  
Pelvic Fin

Quebecius quebecensis (Whiteaves 1889) is a porolepiform crossopterygian related to Glyptolepis. A large nariodal, a large tabular, a separate intertemporal, and a large fused nasosupraorbital are features of Quebecius that characterize it as a porolepiform. The small size of the operculum, median extrascapular larger than the lateral one, small lower squamosals, and deep maxilla are additional features separating Quebecius from Glyptolepis. As in Glyptolepis, the median fins are not lobed. The pectoral fin possesses a long fleshy lobe. The internal, ventral side of the broadly based pelvic fin suggests that the internal axis has shifted towards the body. Pectoral fins with a long fleshy lobe are a common feature of porolepiforms, but lobed bases in the pelvic and unpaired fins are a feature found in Holoptychius, and not in Glyptolepis and Quebecius. Quebecius quebecensis is conspecific with Quebecius williamsi Schultze 1973, mistakenly described as an onychodont crossopterygian.

Swimming behavior of juvenile giant scallop, Placopecten magellanicus, in relation to size and temperature

1991 ◽  
Vol 69 (8) ◽  
pp. 2250-2254 ◽  
Author(s):  
J. L. Manuel ◽  
Michael J. Dadswell
Keyword(s):  
Water Column ◽  
Significant Relationship ◽  
Size Range ◽  
Shell Height ◽  
Swimming Behavior ◽  
The Body ◽  
Placopecten Magellanicus ◽  
Body Angle ◽  
The Mean ◽  
Increasing Temperature

Juvenile scallops (shell height 4–35 mm) were stimulated to swim in an aquarium using a whelk, and their swimming was recorded and analyzed using a videocassette recorder. Scallops ascended in the water column in straight, spiral, or twisting patterns, and the majority never swam horizontally. Two types of swimming were observed. Stable swimming, with a consistent body angle (the angle that the scallop makes with the horizon), was recorded over the size range of scallops examined. In stepwise swimming, the body angle alternated between steep (98 ± 13 (SD)) and more horizontal angles (51 ± 9°). Stepwise swimming was observed among the smaller (mean ± SD = 8 ± 3 mm) scallops. Maximum and mean velocities were positively correlated with both shell height and temperature. Clap rate (Cr) increased with increasing temperature (Cr = 0.29T (°C) + 1.3). Body angle expressed a significant relationship with shell height. Below 10 mm shell height the mean angle was 82°; between 30 and 35 mm the mean angle was 38°.

KINEMATICS OF PECTORAL FIN LOCOMOTION IN THE BLUEGILL SUNFISH LEPOMIS MACROCHIRUS

1994 ◽  
Vol 189 (1) ◽  
pp. 133-161 ◽  
Author(s):  
A Gibb ◽  
B Jayne ◽  
G Lauder
Keyword(s):  
Swimming Speed ◽  
Beat Frequency ◽  
Lepomis Macrochirus ◽  
Force Balance ◽  
Total Force ◽  
Bluegill Sunfish ◽  
Pectoral Fin ◽  
Lateral Projection ◽  
Pectoral Fins ◽  
Distal Edge

The pectoral fins of ray-finned fishes are flexible and capable of complex movements, and yet little is known about the pattern of fin deformation during locomotion. For the most part, pectoral fins have been modeled as rigid plates. In order to examine the movements of different portions of pectoral fins, we quantified the kinematics of pectoral fin locomotion in the bluegill sunfish Lepomis macrochirus using several points on the distal fin edge and examined the effects of swimming speed on fin movements. We simultaneously videotaped the ventral and lateral views of pectoral fins of four fish swimming in a flow tank at five speeds ranging from 0.3 to 1.1 total lengths s-1. Four markers, placed on the distal edge of the fin, facilitated field-by-field analysis of kinematics. We used analyses of variance to test for significant variation with speed and among the different marker positions. Fin beat frequency increased significantly from 1.2 to 2.1 Hz as swimming speed increased from 0.3 to 1.0 total lengths s-1. Maximal velocities of movement for the tip of the fin during abduction and adduction generally increased significantly with increased swimming speed. The ratio of maximal speed of fin retraction to swimming speed declined steadily from 2.75 to 1.00 as swimming speed increased. Rather than the entire distal edge of the fin always moving synchronously, markers had phase lags as large as 32 with respect to the dorsal edge of the fin. The more ventral and proximal portions of the fin edge usually had smaller amplitudes of movement than did the more dorsal and distal locations. With increased swimming speed, the amplitudes of the lateral and longitudinal fin movements generally decreased. We used two distal markers and one basal reference point to determine the orientation of various planar fin elements. During early adduction and most of abduction, these planar fin elements usually had positive angles of attack. Because of fin rotation, angles of attack calculated from three-dimensional data differed considerably from those estimated from a simple lateral projection. As swimming speed increased, the angles of attack of the planar fin elements with respect to the overall direction of swimming approached zero. The oscillatory movements of the pectoral fins of bluegill suggest that both lift- and drag-based propulsive mechanisms are used to generate forward thrust. In addition, the reduced frequency parameter calculated for the pectoral fin of Lepomis (sigma=0.85) and the Reynolds number of 5x10(3) indicate that acceleration reaction forces may contribute significantly to thrust production and to the total force balance on the fin.

scholarly journals Heterocercal tail function in leopard sharks: a three-dimensional kinematic analysis of two models

1996 ◽  
Vol 199 (10) ◽  
pp. 2253-2268 ◽  
Author(s):  
L Ferry ◽  
G Lauder
Keyword(s):  
High Speed ◽  
Classical Model ◽  
Three Dimensional ◽  
Strong Support ◽  
Three Dimensions ◽  
Video Cameras ◽  
Leopard Shark ◽  
Triakis Semifasciata ◽  
Leopard Sharks ◽  
Tail Function

Two different models have been proposed to explain the function of the heterocercal tail in shark locomotion. The classical model proposes that, as a result of lift generated by the tail as it beats, the net force acting on the tail is directed dorsally and anteriorly. In contrast, Thomson's model suggests that the tail generates a net force directed through the shark's center of gravity, i.e. ventrally and anteriorly. In this study, we evaluate these two models by describing the three-dimensional kinematics of the heterocercal tail in the leopard shark Triakis semifasciata during swimming. Lateral and posterior views of the tail were examined from four individuals swimming in a flow tank at 1.2 L s-1 (where L is total length) using two high-speed video cameras filming simultaneously at 250 fields s-1. These two simultaneous views allowed eight landmarks on the tail to be followed in three dimensions through time. These landmarks allowed the tail to be divided into separate surfaces whose orientation over time was calculated. Points located anteriorly on the tail go through significantly smaller excursions and reach their maximum lateral excursion significantly earlier in the beat cycle than points on the trailing edge of the tail. Three-dimensional angle calculations show that the terminal lobe leads the ventral lobe through a beat, as predicted by the classical model. Dye-stream visualizations confirmed that this pattern of movement deflects water ventrally and posteriorly to the moving tail, providing strong support for the classical model. Additionally, our results show that a three-dimensional analysis is critical to understanding the function of the heterocercal tail.

scholarly journals Molecular mechanisms underlying the exceptional adaptations of batoid fins

2015 ◽  
Vol 112 (52) ◽  
pp. 15940-15945 ◽  
Author(s):  
Tetsuya Nakamura ◽  
Jeff Klomp ◽  
Joyce Pieretti ◽  
Igor Schneider ◽  
Andrew R. Gehrke ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Integration Site ◽  
The Body ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Bony Fishes ◽  
Genetic Module ◽  
Fin Development ◽  
Pelvic Fin

Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)–Fibroblast growth factor (Fgf)–Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies.

Bioinspiration From Flexible Propulsors: Organismal Design, Mechanical Properties, Kinematics and Neurobiology of Pectoral Fins in Labrid Fishes

2017 ◽  
Vol 51 (5) ◽  
pp. 23-34 ◽  
Author(s):  
Mark W. Westneat ◽  
Brett R. Aiello ◽  
Aaron M. Olsen ◽  
Melina E. Hale
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
High Performance ◽  
Neural Control ◽  
Three Dimensional ◽  
Marine Species ◽  
Flexural Stiffness ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Flexible Fin

AbstractLabrid fishes use their pectoral fins for efficient high-speed cruising behavior, as well as for precision maneuvering in complex environments, making them good models for biomimicry applications in propulsor technology for aquatic vehicles. Lift-based labriform locomotion is a form of aquatic flight used by many species and is the sole mode of transport across most speeds by some of the largest wrasses and parrotfishes on coral reefs. Although basic and applied research has explored fin design in several species utilizing labriform propulsion, a detailed analysis of fin anatomy, fin mechanical properties, and well-resolved three-dimensional (3D) kinematics in high-performance aquatic flyers has not yet been attained. Here, we present recent research on fin structure, fin flexural stiffness, sensory abilities of fins, and a novel 3D approach to flexible fin kinematics. Our aims are to outline important future directions for this field and to assist engineers attempting biomimicry of maneuverable fin-based locomotion for applications in robotics. First, we illustrate the anatomical structure and branching patterns of the pectoral fin skeleton and the muscles that drive fin motion. Second, we present data on the flexural stiffness of pectoral fins in the parrotfish (Scarus quoyi), setting up a stiffness field that gives the fin propulsor its passive mechanical properties and enables hydrodynamically advantageous fin deformations during swimming. Third, we present 3D reconstructions of the kinematics of high-performance Scarus fins that greatly enhance our ability to reproduce fin motions for engineering applications and also yield insight into the functional role of the fin stiffness field. Lastly, recent work on mechanosensation is illustrated as key to understanding sensorimotor control of labriform locomotion. Research on pectoral fin structure, function, and neural control in large marine species with high-performance wing-like fins is important to the comparative biology of locomotion in fishes, and we suggest it is a productive area of research on fin function for applications in the design of quiet, efficient propulsors.

Mechatronic Design and Maneuverability Analysis of a Novel Robotic Shark for Coral Reef Detection

2021 ◽  
Author(s):  
Liyang Gao ◽  
Peng Li ◽  
Hongde Qin ◽  
Zhongchao Deng
Keyword(s):  
Coral Reef ◽  
Dynamic Model ◽  
Swimming Speed ◽  
Three Dimensional ◽  
Pectoral Fin ◽  
Spiral Motion ◽  
Pectoral Fins ◽  
Mechatronic Design ◽  
Grid Technique ◽  
Turning Radius

Abstract In this paper, mechatronic design of a novel robotic shark for coral reef detection is presented. To obtain good maneuverability, a barycenter regulating device is designed to assist the posture adjustment of the robotic shark at low speed. Based on STAR-CCM+ software, the lift coefficients and drag coefficients of pectoral fin are calculated using overlapping grid technique. Based on Newton-Euler approach, a dynamic model with particular consideration of pectoral fins for three-dimensional motion is established. A CPG controller is used to generate rhythmic motion of each joint. Furthermore, based on the dynamic model, three-dimensional trajectory of spiral motion and swimming speed in different oscillation parameters are simulated. The results show that swimming speed of the robotic shark can be improved by increasing the amplitude and frequency or decreasing the phase difference. Also, oscillation frequency plays a more significant role. Furthermore, under the action of single pectoral fin, the robotic shark can achieve spiral motion and the turning radius is about 35.8m under the parameters set in this article.

Labriform propulsion in fishes: kinematics of flapping aquatic flight in the bird wrasse Gomphosus varius (Labridae)

1997 ◽  
Vol 200 (11) ◽  
pp. 1549-1569 ◽  
Author(s):  
J Walker ◽  
M Westneat
Keyword(s):  
Center Of Mass ◽  
Three Dimensional ◽  
Lateral View ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Video Images ◽  
Stationary Observer ◽  
Swimming Mode ◽  
Total Body ◽  
Unsteady Effects

Labriform, or pectoral fin, propulsion is the primary swimming mode for many fishes, even at high relative speeds. Although kinematic data are critical for evaluating hydrodynamic models of propulsion, these data are largely lacking for labriform swimmers, especially for species that employ an exclusively labriform mode across a broad range of speeds. We present data on pectoral fin locomotion in Gomphosus varius (Labridae), a tropical coral reef fish that uses a lift-based mechanism to fly under water at sustained speeds of 1­6 total body lengths s-1 (TL s-1). Lateral- and dorsal-view video images of three fish swimming in a flow tank at 1­4 TL s-1 were recorded at 60 Hz. From the two views, we reconstructed the three-dimensional motion of the center of mass, the fin tip and two fin chords for multiple fin beats of each fish at each of four speeds. In G. varius, the fin oscillates largely up and down: the stroke plane is tilted by approximately 20 ° from the vertical. Both frequency and the area swept by the pectoral fins increase with swimming speed. Interestingly, there are individual differences in how this area increases. Relative to the fish, the fin tip in lateral view moves along the path of a thin, inclined figure-of-eight. Relative to a stationary observer, the fin tip traces a sawtooth pattern, but the teeth are recumbent (indicating net backwards movement) only at the slowest speeds. Distal fin chords pitch nose downward during the downstroke and nose upward during the upstroke. Hydrodynamic angles of attack are largely positive during the downstroke and negative during the upstroke. The geometry of the fin and incident flow suggests that the fin is generating lift with large upward and small forward components during the downstroke. The negative incident angles during the upstroke suggest that the fin is generating largely thrust during the upstroke. In general, the large thrust is combined with a downward force during the upstroke, but the net backwards motion of the fin at slow speeds generates a small upward component during slow swimming. Both the alternating sign of the hydrodynamic angle of attack and the observed reduced frequencies suggest that unsteady effects are important in G. varius aquatic flight, especially at low speeds. This study provides a framework for the comparison of aquatic flight by fishes with aerial flight by birds, bats and insects.

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