Hydrodynamics of a biologically inspired tandem flapping foil configuration |
| |
Authors: | Imran Akhtar Rajat Mittal George V Lauder Elliot Drucker |
| |
Institution: | (1) Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052, USA;(2) Present address: Department of Engineering Science and Mechanics, Virginia Tech., Blacksburg, VA 24061, USA;(3) Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA;(4) Present address: Washington Trout, Duvall, WA 98019, USA |
| |
Abstract: | Numerical simulations have been used to analyze the effect that vortices, shed from one flapping foil, have on the thrust
of another flapping foil placed directly downstream. The simulations attempt to model the dorsal–tail fin interaction observed
in a swimming bluegill sunfish. The simulations have been carried out using a Cartesian grid method that allows us to simulate
flows with complex moving boundaries on stationary Cartesian grids. The simulations indicate that vortex shedding from the
upstream (dorsal) fin is indeed capable of increasing the thrust of the downstream (tail) fin significantly. Vortex structures
shed by the upstream dorsal fin increase the effective angle-of-attack of the flow seen by the tail fin and initiate the formation
of a strong leading edge stall vortex on the downstream fin. This stall vortex convects down the surface of the tail and the
low pressure associated with this vortex increases the thrust on the downstream tail fin. However, this thrust augmentation
is found to be quite sensitive to the phase relationship between the two flapping fins. The numerical simulations allows us
to examine in detail, the underlying physical mechanism for this thrust augmentation.
|
| |
Keywords: | Flapping foil Complex moving boundaries Thrust augmentation Fish fins Fish locomotion |
本文献已被 SpringerLink 等数据库收录! |
|