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Titolo:
A hydrodynamic analysis of fish swimming speed: Wake structure and locomotor force in slow and fast labriform swimmers
Autore:
Drucker, EG; Lauder, GV;
Indirizzi:
Univ Calif Irvine, Dept Ecol & Evolutionary Biol, Irvine, CA 92697 USA Univ Calif Irvine Irvine CA USA 92697 utionary Biol, Irvine, CA 92697 USA Harvard Univ, Museum Comparat Zool, Cambridge, MA 02138 USA Harvard Univ Cambridge MA USA 02138 omparat Zool, Cambridge, MA 02138 USA
Titolo Testata:
JOURNAL OF EXPERIMENTAL BIOLOGY
fascicolo: 16, volume: 203, anno: 2000,
pagine: 2379 - 2393
SICI:
0022-0949(200008)203:16<2379:AHAOFS>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUNFISH LEPOMIS-MACROCHIRUS; AQUATIC FLIGHT; INSECT FLIGHT; MUSCLE; KINEMATICS; MECHANISMS; CALIFORNIA; FREQUENCY; STABILITY; CYCLE;
Keywords:
swimming; pectoral fin locomotion; flow visualization; hydrodynamics; digital particle image velocimetry; black surfperch; Embiotoca jacksoni; bluegill sunfish; Lepomis macrochirus;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Drucker, EG Univ Calif Irvine, Dept Ecol & Evolutionary Biol, Irvine, CA 92697 USA Univ Calif Irvine Irvine CA USA 92697 l, Irvine, CA 92697 USA
Citazione:
E.G. Drucker e G.V. Lauder, "A hydrodynamic analysis of fish swimming speed: Wake structure and locomotor force in slow and fast labriform swimmers", J EXP BIOL, 203(16), 2000, pp. 2379-2393

Abstract

Past study of interspecific variation in the swimming speed of fishes has focused on internal physiological mechanisms that may limit the ability of locomotor muscle to generate power. In this paper, we approach the questionof why some fishes are able to swim faster than others from a hydrodynamicperspective, using the technique of digital particle image velocimetry which allows measurement of fluid velocity and estimation of wake momentum andmechanical forces for locomotion. We investigate the structure and strength of the wake in three dimensions to determine how hydrodynamic force varies in two species that differ markedly in maximum swimming speed. Black surfperch (Embiotoca jacksoni) and bluegill sunfish (Lepomis macrochirus) swim at low speeds using their pectoral fins exclusively, and at higher speeds switch to combined pectoral and caudal fin locomotion. E, jacksoni can swim twice as fast as similarly sized L, macrochirus using the pectoral fins alone. The pectoral fin wake of black surfperch at all speeds consists of two distinct vortex rings linked ventrally. As speed increases from 1.0 to 3.0 L s(-1), where L is total body length, the vortex ring formed on the fin downstroke reorients to direct force increasingly downstream, parallel to thedirection of locomotion. The ratio of laterally to downstream-directed force declines from 0.93 to 0.07 as speed increases. In contrast, the sunfish pectoral fin generates a single vortex ring per fin beat at low swimming speeds and a pair of linked vortex rings (with one ring only partially complete and attached to the body) at maximal labriform speeds. Across a biologically relevant range of swimming speeds, bluegill sunfish generate relatively large lateral forces with the paired fins: the ratio of lateral to downstream force remains at or above 1.0 at all speeds. By increasing wake momentum and by orienting this momentum in a direction more favorable for thrust than for lateral. force, black surfperch are able to swim at twice the speed of bluegill sunfish using the pectoral fins. In sunfish, without a reorientation of shed vortices, increases in power output of pectoral fin muscle would have little effect on maximum locomotor speed. We present two hypotheses relating locomotor stability, maneuverability and the structure of the vortex wake. First, at low speeds, the large lateral forces exhibited by both species may be necessary for stability. Second, we propose a potential hydrodynamic trade-off between speed and maneuverability that arises as a geometric consequence of the orientation of vortex rings shed by the pectoralfins. Bluegill sunfish may be more maneuverable because of their ability to generate large mediolateral force asymmetries between the left- and right-side fins.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/03/20 alle ore 12:46:44