Flow Past a Cylinder with a Flapping Element Attached to Its End

Abstract

The flows around a circular cylinder with a spli tter plate attached along the centerline of the wake are studied numerically and experimentally. Unsteady numerical computations were performed for various plate lengths at the Reynolds number of 100,000. The standard high -Reynolds number turbulence mode l with wall function has been used in the unsteady Reynolds -averaged Navier -Stokes calculations. Experimentally, the drag forces on the cylinder/splitter combination were measured at Reynolds number ranging from 80,000 to 13 0,000. The numerical results a re presented and, where appropriate, compared with measured data. The compar isons show that the numerical computations agree well with experimental data. The Strouhal number varies in a non -monotonic fashion with the plate length. Drag reduction occurs at all plate lengths calculated with the maximum of about 30% at l/d of 1.2. The amplitude of the lift coefficient oscillation decreases significantly with the increasing plate length. The results for a case with a flapping splitter plate are also report ed.