Journal of Fluid Mechanics


Uncovering the physics of flapping flat plates with artificial evolution

a1 Graduate Aeronautics Laboratories, Option of Bioengineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA

Article author query
milano m   [Google Scholar] 
gharib m   [Google Scholar] 


We consider an experiment in which a rectangular flat plate is flapped with two degrees of freedom, and a genetic algorithm tunes its trajectory parameters so as to achieve maximum average lift force, thus evolving a population of trajectories all yielding optimal lift forces. We cluster the converged population by defining a dynamical formation number for a flapping flat plate, thus showing that optimal unsteady force generation is linked to the formation of a leading-edge vortex with maximum circulation. Force and digital particle image velocimetry measurements confirm this result.

(Received March 29 2005)
(Revised April 13 2005)