THE DRAG, LIFT AND STROUHAL NUMBER OF A CIRCULAR-SECTION CYLINDER WITH A CONIC DISTURBANCE AT SUBCRITICAL REYNOLDS NUMBERS

Through numerical simulations, the flow past a circular-section cylinder with a conic disturbance is investigated at subcritical Reynolds numbers of 10(2), 10(3) and 10(4). At higher Reynolds numbers, LES is employed in simulating the turbulence transition in the near wake. Computations with a series of parameters, the wavelength and wave steepness, are carried out. Generally, the drag of conic cylinder is gradually increased with the increasing wave steepness and in most cases greater than that of the cylinder without disturbance. However, the total lift in most cases is obviously reduced. The phenomenon of local minimum is found out in variation of drag and lift. The introduction of conic disturbance also leads to the decrease of frequency of vortex shedding as the wave steepness increases.