Control of the secondary cross-flow instability using localized suction

• Published in: Journal of fluid mechanics Vol. 706; pp. 470 - 495
• Main Authors: Friederich, Tillmann, Kloker, Markus J.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 10.09.2012
• Subjects: Base flow; Boundaries; Boundary layer; Computational fluid dynamics; Exact sciences and technology; Fluid dynamics; Fluid flow; Fluid mechanics; Fundamental areas of phenomenology (including applications); Hydrodynamic stability; Instability; Numerical analysis; Physics; Secondary instability; Stability; Turbulence; Turbulence control; Turbulent flow; Turbulent flows, convection, and heat transfer; Walls; instability control; drag reduction; transition to turbulence; Skin friction; Drag reduction; Aspiration; Digital simulation; Control systems; Modelling; Delays; Secondary flow; Turbulent laminar transition
• ISSN: 0022-1120; 1469-7645
• DOI: 10.1017/jfm.2012.269

Transition control by suction in a three-dimensional boundary-layer flow subject to cross-flow instability is investigated using direct numerical simulation. Whereas the classical application of (homogeneous) suction at the wall is aimed at modifying the quasi-two-dimensional base flow to weaken primary cross-flow instability, here the three-dimensional nonlinear disturbance state with large-amplitude steady cross-flow vortices (CFVs) is controlled. Strong, localized ‘pinpoint’ suction is shown to be suitable for altering the CFVs and the associated flow field such that secondary instability is weakened or even completely suppressed. Thus significant delay of transition to turbulence can be achieved.