The passive control of wake flow behind a circular cylinder by parallel dual plates

In this paper, the wake control of a circular cylinder by dual plates symmetrically attached at the rear surface is numerically investigated within the laminar flow regime. The two flat plates are arranged in parallel form, and the attachment angle is varied in the range theta(f)=0-90 degrees. In comparison to the use of a single splitter plate, the dual plates cause increased drag reduction and stronger wake suppression at relatively shorter plate lengths. It is shown that the attachment angle has a crucial effect on the control efficiency, and the most effective range associated with the maximum drag reduction is between 40 degrees <= theta(f) <= 50 degrees. Within this regime, the free shear layers reattach on the outside surface of the control plates. The potential mechanism responsible for the wake control is suggested based on a comparison with other passive control configurations. (c) 2012 Elsevier Ltd. All rights reserved.