... particle image velocimetry (PIV). Trout of each size class preferentially swam in vortices rather than the freestream, but the capacity to flow refuge varied according to the ratio of vortex width to fish length (W V : L F). Consistent refuging behavior was exhibited when W V : L F ≥1.5. All size classes...

... of multiple vortices along the body of the snake due to its undulation. The 3D structure of the vortices generally consisted of paired vortex tubes, some of which were linked together to form a hairpin structure. The observations match predictions from computational fluid dynamic studies of other anguilliform...

... image velocimetry (PIV) revealed that the formation of a vortex, rather than the expulsion of fluid between two closing body surfaces, generates propulsion in rusty crayfish. PIV also revealed that the pleopods (ventral abdominal appendages) contribute to the momentum generated by the tail. To our...

..., kinematics and oxygen consumption in a typical laboratory flume versus a more turbulent, semi-natural flow, which may have implications for behaviour and energetics measured in the lab. Vortex Eddy Gait Swimming kinematics Metabolism Space use The complex habitats in which many marine...

.... Hydrodynamics Biomechanics Propulsion Fish Vortex Flexible bending Aquatic animals significantly outperform man-made aquatic vehicles because they are able to move in water with greater efficiency and maneuverability (Bandyopadhyay, 2005 ; Gemmell et al., 2013). Animals achieve these performance...

...Daegyoum Kim; Morteza Gharib SUMMARY Several characteristics of drag-based paddling propulsion are studied with a simple mechanical model and a measurement technique for mapping three-dimensional flow fields. In drag-based propulsion, the temporal change of the vortex strength is an important...

... of the caudal fin. * Author for correspondence (e-mail: [email protected]) 30 7 2008 © The Company of Biologists Limited 2008 2008 fish pitching stabilization caudal fin-wave propagation vortex stereoscopic-DPIV parrot cichlid The shape of the caudal fin of a fish...

..., quasi-steady flow is assumed and the flow analysis is based on velocity and/or vorticity fields measured at a single time instant during the stroke cycle. The assumption of quasi-steady flow leads to neglect of unsteady (time-dependent) wake vortex added-mass effects,which can contribute significantly...

... model provides an approach to empirically deduce swimming and flying forces based on the measurement of velocity and vortex added-mass in the animal wake. The model is contingent on the identification of the vortex boundary in the wake. This paper demonstrates the application of that method to a case...

...-mass contribution from fluid surrounding vortices in the wake, and proceeds identically to a measurement of the added-mass traditionally associated with fluid surrounding solid bodies. It is demonstrated that the velocity/pressure perspective is equivalent to the vorticity/vortex-added-mass approach...

...,and formed below the keels and increased in circulation as pitch angle became more negative. Vortices also formed along the eye ridges of all boxfishes. In the spotted boxfish, which is largely trapezoidal in cross section, consistent dorsal vortex growth posterior to the eye ridge was also present. When all...

.... During this gait,body amplitudes and curvatures are much larger than those of trout swimming at an equivalent flow velocity in the absence of a cylinder. Tail-beat frequency is not only lower than might be expected for a trout swimming in the reduced flow behind a cylinder, but also matches the vortex...

...Tyson L. Hedrick; Bret W. Tobalske; Andrew A. Biewener SUMMARY Birds and bats are known to employ two different gaits in flapping flight,a vortex-ring gait in slow flight and a continuous-vortex gait in fast flight. We studied the use of these gaits over a wide range of speeds (1-17 ms -1...

.... In the experiments described here, the phase relationship between the tailbeat cycle and the inflection point cycle can be used as a first approximation of the phase between the proto-vortex and the tailbeat cycle. Proto-vortices are shed at the tail as body vortices at roughly the same time as the inflection points...

... the tail tip vortex that is generated with the initial stroke, (ii) using a moderately flexible tail, and (iii) introducing a specific delay between the initial stroke and the return stroke. Experiments were performed with a new computer-controlled fish-tail simulation apparatus, and the results confirm...

... or more of the default values, used in the program for calculating induced, profile and parasite power, may be in need of downward revision. 15 9 1988 © 1989 by Company of Biologists 1989 bird flight vortex wake A method for calculating the power required by a flying bird...