Full text loading...
Schematic showing the problem geometry and important parameters relevant to the combined forced oscillation and the circular cylinder model. The streamwise direction is the direction.
Motion phased-locked vorticity isocontours (lines) and root mean square vorticity (grayscale) taken at the motion phase . The near-wake vorticity is shown for different phase differences between the two imposed oscillatory motions. Of particular interest is the asynchronous (unlocked) wake with the imposed translational motion for the phases and .
Lissajous pattern defined horizontally with the translational forcing mechanism and vertically with lift (top) or drag (bottom) coefficient.
Typical flow features for different imposed phase differences. Top: single row of vortices transitioning downstream to a double row followed by a further secondary instability in the far wake . Center: double row of vortices followed by a quasiperiodic pattern . Bottom: chaotic pattern of vortices . The domain of the numerical simulation was extended to downstream for these cases.
Poincaré map for two typical unlocked regimes for . Left: quasiperiodic behavior for . Right: chaotic regime for . The phase diagram shows the horizontal and the vertical velocities at downstream on the centerline.
Summary of the synchronization around the unlocked regime. L, QP, and C stand for locked on, quasiperiodic, and chaotic, respectively. The unlocked regimes (UL) for the experimental results are likely to be chaotic. and stand for forced frequency and natural frequency for a fixed cylinder.
Article metrics loading...