CHARACTERISTICS OF FLOWS OVER AN ASYMMETRICALLY GROOVED CIRCULAR-CYLINDER IN THE TRANSITIONAL REGIMES

The transition characteristics of flows over an asymmetrically grooved circular cylinder have been investigated experimentally. Two flow con figurations, subcritical-critical and subcritical-upper supercritical, respectively have been identified within the Reynolds number range 4. 4 x 10(4)-1.3 x 10(5). It was found that the flow on the smooth side i s within the subcritical regime of a smooth cylinder throughout the ra nge studied, while higher flow regimes occur on the grooved side. At t he Reynolds number between 7.0 x 10(4) and 7.2 x 10(4) the flow on the grooved side oscillates between the critical and upper supercritical flow regimes, which is accounted for the formation and burst of the se paration bubble on the grooved side.