Controlled oscillations of a cylinder: a new wake state

The wake states resulting from the controlled oscillation of a cylinder transverse to the free stream are presented. A new wake state is revealed by instantaneous measurements of the total and vortex lift phases, and the phase-referenced, quantitative wake structure. This intermediate wake state occurs at oscillation frequencies between the previously observed low- and high-frequency states. It cannot be deduced from classical, time-averaged representations of the loading on the cylinder. (C) 2002 Elsevier Science Ltd. All rights reserved.