Views
3 years ago

passive and active flow control by swimming fishes and mammals

passive and active flow control by swimming fishes and mammals

Annu. Rev. Fluid. Mech.

Annu. Rev. Fluid. Mech. 2006.38:193-224. Downloaded from arjournals.annualreviews.orgby WEST CHESTER UNIVERSITY on 12/20/05. For personal use only.Figure 13Sample images from high-speed videos of fish fin function showing the considerable flexibilityof both individual fin rays and the entire fin. (a) Bluegill sunfish pectoral fin conformationduring steady swimming. Arrow points to the wave of bending that travels from base to tip ofthe upper fin rays. (b) Pectoral fin maneuvering in yellow perch, Perca flavescens. Note how thelower (ventral) edge of the fin (black arrow) leads the rest of the fin out from the body.(c) Pectoral fin conformation during steady swimming in killifish, Fundulus. Both upper andlower fin edges (arrows) lead the middle of the fin as it moves away from the body. (d ) Dorsalfin conformation during maneuvering in bluegill sunfish. Note that the whole fin is bent intoalmost a 90 ◦ angle but that individual fin rays are relatively straight (Panel d modified fromStanden & Lauder 2005.)and dorsal and anal fin function during both propulsion and maneuvering. Figure 14shows representative experimental hydrodynamic data from the bluegill pectoral fin(Drucker & Lauder 1999). DPIV in three separate orthogonal planes of sunfish swimmingat 0.5 Ls −1 reveals that each plane shows formation of a single vortex. Bluegillsunfish swimming at 0.5 Ls −1 use only their pectoral fins for propulsion and there isa pause between each fin beat during which vorticity is shed from the fin. Significantdownstream momentum is added to the flow as the fin moves out (away) from thebody (Figure 14d, frontal plane), indicating that thrust is generated by pectoral finsduring both out and back fin movements. A schematic reconstruction of the vortexwake by sunfish swimming at 0.5 Ls −1 is shown in Figure 15a, where the singlefin forces estimated from the vortex wake are given (Drucker & Lauder 1999). Asspeed swimming speed increases, the formation of pectoral vortex rings changes andadditional vorticity is shed on the upstroke (Figure 15b), producing two rings, oneof which remains attached to the body until it drifts back and is shed as a secondring.In addition, differences in vortex wake structure are found among species and asswimming speed changes, which may partially explain why fish have gait transitions.210 Fish·Lauder

Annu. Rev. Fluid. Mech. 2006.38:193-224. Downloaded from arjournals.annualreviews.orgby WEST CHESTER UNIVERSITY on 12/20/05. For personal use only.Figure 14Experimental hydrodynamic data on fluid flows induced by the pectoral fin in freely swimmingbluegill sunfish at 0.5 Ls −1 . Pectoral fin particle image velocimetry data obtained in separateexperiments from three separate orthogonal planes (shown above) are illustrated. In thefrontal and parasagittal planes (a and b), flow is from left to right; in the transverse plane(c), flow is from behind and out of the page in the vector plot below. Fluid flow patterns areshown for two times during the fin beat: The first row of plots (d ) indicates flow at the timeof fin beat reversal, the transition from movement out to movement toward the body. Thelower three panels (e) show flow during the mid-to-late upstroke. The mean free-streamvelocity of 10.5 cm s −1 was subtracted from all vectors in the frontal and parasagittal planes.Yellow arrow = 20 cm s −1 ; bar = 1 cm. (Modified from Drucker & Lauder 1999.)Bluegill sunfish use only their pectoral fins to generate locomotor force over a speedrange of 0.5 Ls −1 to 1.1 Ls −1 , and above this speed they recruit additional fins togenerate propulsive force (Drucker & Lauder 2000). Why do bluegill change gaits byadding the tail and dorsal and anal fins as thrust generators? Surfperch (Embiotoca jacksoni)continue to use their pectoral fins throughout a wide range of swimming speeds,www.annualreviews.org • Fish and Mammal Locomotion 211

Numerical Study of Passive and Active Flow Separation Control ...
Numerical Study of Passive and Active Flow Separation Control ...
Passive, Semi-Active and Active Vibration Control Systems for ...
Fundamentals of actively controlled flows with trapped vortices ...
An Exploration of Passive and Active Flexibility in Biolocomotion ...
Development of passive and active noise control for next ... - HMMH
Active control of passive acoustic fields: Passive synthetic ...
Passive layer optimization for active absorbers in flow duct ...
active and passive vibration control of structures - Cism
Passive and active control of the wake behind axisymmetric bluff ...
Comparison between Passive and Semi Active Controlled Suspension
Passive Energy Dissipation and Active Control - Index of - Free
active and passive vibration control of structures - CISM
active and passive vibration control of structures - CISM
Passive flow control around a 2D semi-circular cylinder using ...
Functional morphology of the fin rays of teleost fishes - Mathematics
Hydrodynamic stability of swimming in ostraciid fishes - California ...
Hybrid passive/active absorbers for flow ducts - Centre Acoustique ...
A Unifying Passivity Framework for Network Flow Control
A Unifying Passivity Framework for Network Flow Control
Turbulence and Coarsening in Active and Passive ... - Sapienza
One dimensional study of a module for active/passive control of both ...
Decentralised feedback control for active absorption in flow ducts
Turbulence and Coarsening in Active and Passive Binary Mixtures
Passive Mixing Control via Lobed Injectors in High-Speed Flow
Combined Design and Robust Control of a Vehicle Passive/Active ...
1 Investigation of pulsed actuators for active flow control using ...
Passive flow control around a wall-mounted finite cylinder - Pegasus
Active control of the flow behind a two-dimensional bluff body in ...
numerical simulation of active flow control based on ... - BBAA VI