Composite active drag control in turbulent channel flows
Jie Yao, Xi Chen, Fazle Hussain
Abstract
A composite drag control (CDC) combining the opposition (OC) and spanwise opposed wall-jet forcing (SOJF) methods is investigated. A maximum drag reduction of about 33% is obtained for CDC -- much higher than that produced by either individual method (namely, 19% for SOJF and 23% for OC). Flow analysis shows that CDC can take advantage of both OC and SOJF methods to better suppress drag producing near-wall turbulent structures --vortices and streaks. Our results suggest prospects of employing a composite control strategy for effective skin friction drag reduction, particularly at very high Reynolds numbers.
Topics & Concepts
DragParasitic dragTurbulenceMechanicsReynolds numberFlow control (data)VortexComposite numberFlow separationPhysicsMaterials scienceEngineeringComposite materialTelecommunicationsFluid Dynamics and Turbulent FlowsHeat Transfer MechanismsAerodynamics and Acoustics in Jet Flows