1. The robotic flapping foil apparatus used to test the hydrodynamic function of shark skin and biomimetic models.
The robotic flapping foil apparatus used to test the hydrodynamic function of shark skin and biomimetic models. Both rigid (f) and flexible foils with attached riblet material or shark skin are clamped in the flapper shaft (fs) and immersed in the flow tank. Robot motion is driven by a heave motor (hm) and a pitch motor (pm), mounted on air bearings (ab), so that the equilibrium position is only dependent on the cables (c). There is no cable effect as all tests are conducted at the equilibrium position (see Lauder et al., 2007; Lauder, 2011a; Lauder, 2001b) for details of this testing apparatus. Tuning the flume speed to match flapper thrust enables one to find the self-propelled speed (see text). Bumpers (b) limit large deflections. Note that the robot can drive two separate foils, but only one is used during the experiments here. The blue arrow indicates the flow direction. The rigid foil shown here is 19 cm in height, 6.85 cm in chord length (Fig. 2), but the membrane foils tested were a different shape (see text and Fig. 3 for a description).
Johannes Oeffner, and George V. Lauder J Exp Biol 2012;215:
© 2012.