Numerical simulations of flows over a forced oscillating cylinder

A numerical study of incompressible laminar flow past a circular cylinder forced to oscillate longitudinally, transversely and at an angle to the uniform freestream is performed using the dynamic mesh method. The simulations are conducted at a fixed Reynolds number of 80 with amplitude ratios varying between 0.14 to 0.50 and excitation frequency ratios of 0.05 to 3.0. Good agreement to previous experimental and numerical investigations is achieved in the prediction of the lock-on range, force amplifications and vortex shedding modes for longitudinal and transverse oscillations. For excitations at an angle of 60 degrees relative to the oncoming flow, previously identified modes of AI and, AII were successfully predicted. In addition, at higher amplitude ratios the entire synchronised von Karman wake street displayed a deviating effect from the centreline. Analysis of the wake response via phase plane diagrams and the transverse force coefficients revealed two lock-on regions. The extents of these lock-on regions, and the variation of the forces and near wake vortex shedding modes are presented and discussed herein