links: FinalProject2014

References on surface swimming

1.  (Prange1970) Prange, H.D. and Schmidt-Nielsen, K., The Metabolic Cost of Swimming in Ducks, JEB V. 53, p. 763-777 (1970).

Notes on (Prange1970)

2.  Videos

Good video on Duck paddling, running and taking flight (a bit beyond our power capabilities, but cool to watch):

Western Grebes do some very cool "walking on water" during courtship. Video courtesy of Nick Wenner's family friend Glenna Clifton at the Harvard Evolutionary Biology Lab.

3.  Previous duck linkages

University of New South Wales project on the Salters Duck -- OK, actually the "Salters Duck" here is a mechanism for harvesting wave energy.

4.  References from Dave Lentink:

This reference shows leading edge vortices are relevant to understand how ducks swim:

We will approximate drag force assuming the flow is perpendicular, at 90deg angle of attack, time averaged force coefficient estimates can be pulled from this paper that reports them for those conditions:

  • Aigeldinger, T. and Fish F.E., Hydroplaning by Ducklings, JEB 198, 1567–1574 (1995) -- escaping ducklings can do 1.73 m/s (versus more like 0.5 for steady paddling), well above the hull speed for a comparable boat.
    • For animals swimming at the water surface at their hull speed, constructive interference from bow and stern waves traps the animal in a trough, ultimately limiting further increases in speed (Vogel, 1988; Denny, 1993).
    • Paddling by ducklings was characterized by alternate power and recovery sweeps of the hindfeet (Fig. 2A; fields 0–2) as in other semiaquatic paddlers (Fish, 1984). During the power phase, the foot was swept posteriorly through an arc with the interdigital webbing fully spread (abducted). The foot was plantarflexed at the tibiotarsus–tarsometatarsus joint and the digits were dorsiflexed. During the recovery phase, the foot was swept anteriorly as the foot was dorsiflexed. The webbing of the foot was collapsed by adduction and plantarflexion of the digits.

5.  Patents

You never know what you might find:

Page last modified on February 25, 2014, at 10:57 AM