Force reduction on a circular cylinder by two small control cylinders in the wake

Abstract

The present study investigates, using numerical modeling, the interaction between a laminar, uniform and bi-dimensional flow with three circular cylinders. Two small control cylinders are placed symmetrically in the wake of a prin cipal cylinder and induced significant modification in flow topology and aerodynamic coefficients. This type of force control is known in the liter ature as passive wake control. The small control cylinders have a diameter D /8, as D is the diameter of principal cylinder. Numerical simulations are performed for Reynolds number 200.

From the various results obtained in the study, it was shown that for a distance between control and pr incipal center cylinders of 0.7 D in the flow direction and 0.7 D in the transversal flow direction, the mean drag coefficient of principa l cylinder is reduced of 27% comparing with the drag coefficient of an isolated cylinder. However, for the to tal of the three cylinders, drag reduction is only 4%. For this configuration, rms drag and lif t coefficients of principal cylinder are largely reduced, 0.0001 and 0.0036, respectively, comparing with an isolated cylinder, 0.035 and 0.47, respectively.