Flow separation control over a rounded ramp with spanwise alternating wall actuation

Large-eddy simulation of flow over a wall-mounted hump with separation control

Large-Eddy Simulation of Separation Control for Compressible Flow Over a Wall-Mounted Hump

Compressible large-eddy simulations of turbulent flow over a wall-mounted hump with active flow control are performed and compared to previous experiments. We consider a range of Mach numbers from 0.1 to 0.6. Control is applied just before the natural separation point via steady suction and zero-net mass flux oscillatory forcing. Compared with the baseline flow, control shortens the separation ...

Alternating Control Flow Reconstruction

Unresolved indirect branch instructions are a major obstacle for statically reconstructing a control flow graph (CFG) from machine code. If static analysis cannot compute a precise set of possible targets for a branch, the necessary conservative over-approximation introduces a large amount of spurious edges, leading to even more imprecision and a degenerate CFG. In this paper, we propose to lev...

Turbulent Drag Reduction by Spanwise Wall Oscillations

The objective of this paper is to examine the effectiveness of wall oscillation as a control scheme of drag reduction. Two flow configurations are considered: constant flow rate and constant mean pressure gradient. The Navier-Stokes equations are solved using Fourier-Chebyshev spectral methods and the oscillation in sinusoidal form is enforced on the walls through boundary conditions for the sp...

Technical Notes Effects of Actuation Frequency on Flow Control Applied to a Wall-Mounted Hump

ACTIVE flow control, and particularly unsteady mass injection (synthetic jets), promotes reattachment of naturally separated flows and can increase lift and decrease drag on airfoils at high angles of attack [1]. Synthetic-jet actuators are typically characterized by the unsteady momentum coefficient hC i shusihs = 0:5 1U 1c and the actuation frequencyF fXsep=U1, where s andus are the density a...