... in a highly coordinated wing-like manner in order to swim in the intermediate Reynolds number regime ( Re =10–100). The fin and shell kinematics indicate that atlantiid heteropods use unsteady hydrodynamic mechanisms such as clap-and-fling and delayed stall. Unique features of atlantiid heteropod swimming...

... stall effect, and the transition into flow separation. Also, the influence of the delayed stall and flow separation was clearly visible in measurements of instantaneous net force over the wingbeat cycle. Here, we show that, even at reduced frequencies as low as those of large bird flight, unsteady...

... considered (20–1800), when Re was above ∼100, the lift( C̄ L ) and drag( C̄ D ) coefficients were large and varied only slightly with Re (in agreement with results previously published for revolving wings); the large force coefficients were mainly due to the delayed stall mechanism. However, when Re...

... be especially important because insects flap their wings at high angles of attack. An experimental analysis of delayed stall in 2-D showed that flow separates to form a leading edge vortex at angles of attack above 9°, a threshold well below those used by insects( Dickinson and Götz,1993 ). This study also...

... of kinematic variation and to investigate locomotor control in freely moving animals. (e-mail: [email protected] ) 16 9 2002 © The Company of Biologists Limited 2002 2002 unsteady aerodynamics rotational circulation delayed stall Magnus effect attached vortex lift hovering...

... of the traces in Fig.3 illustrate the complex interactions among delayed stall, rotational circulation and wake capture that result from changes in angle of attack and stroke amplitude. At angles of attack of 30 and 50°, the wing generates lift throughout the stroke due to delayed stall ( Fig.3 C–F...