Dynamic reactions of a free-pitching foil to the reverse Karman vortices

In order to understand the energy saving mechanism of fish schooling, the dynamic reactions of a free-pitching downstream foil to the oncoming reverse Karman vortices shed from a flapping leading foil are investigated numerically. When the position of the hindfoil is optimized in a staggered arrangement, a significant augmentation of the thrust efficiency for the whole two-foil system is obtained because of the suction effect of a vortex pair formed at the leading edge of the hindfoil and the guide-plate effect of the hindfoil on the mean-flow jet originated at the trailing edge of the forefoil. (C) 2014 AIP Publishing LLC.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000334179400004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701MechanicsPhysics, Fluids & PlasmasSCI(E)EI5ARTICLEybao@pku.edu.cn; jjtao@pku.edu.cn3null2