ABSTRACT
ABSTRACT: Numerical simulations of laminar, incompressible flow across a transversely oscillating wavy cylinder (the dimensionless wavelength λ/Dm = 2 and 6) have been undertaken by using the conjugating Finite-volume Method with dynamic mesh technique at a fixed Reynolds number of 100 and a fixed oscillation amplitude ratio (Ae/Dm) of 0.4. The effects of the excitation frequency ratios (fe/fs), the dimensionless wavelength λ/Dm, and the flow parameters have been studied. Compared with the straight cylinder, it is observed that the force amplifications, the lock-on range, and the near-wake vortex-shedding modes behind the wavy stay-cable depend upon the shape of wavy cylinder surface. The wavy cylinder of λ/Dm = 2 displayed a similar Lock-on phenomena at the excitation frequency ratios of 0.7 to 1.3 as the straight cylinder and have no apparent drag reduction. But for the wavy cylinder of λ/Dm = 6, the natural St frequencies are still dominant at that region, the mean drag reduction is up to 27% and the fluctuating lift coefficients is close to 0.1 at = 1.1, the wellorganized wake structures are generated behind the wavy cylinder of λ/Dm = 6. Such simulation results will establish a comprehensive database to further our understanding about the physical mechanisms of this fluid-structure interaction problem.
