Laminar boundary-layer control by combined blowing and suction in the presence of surface roughness (Laminar boundary layer control on two dimensional body by combined blowing and suction in presence of roughness, noting skin friction reduction)

1969 ◽  
Vol 3 (3) ◽  
pp. 145-151 ◽  
Author(s):  
G. F. ANDERSON ◽  
V. S. MURTHY ◽  
S. P. SUTERA
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Skin Friction ◽  
Laminar Boundary Layer ◽  
Friction Reduction ◽  
Boundary Layer Control ◽  
Two Dimensional ◽  
Skin Friction Reduction ◽  
Layer Control

Turbulent boundary-layer control with plasma actuators

2011 ◽  
Vol 369 (1940) ◽  
pp. 1443-1458 ◽  
Author(s):  
Kwing-So Choi ◽  
Timothy Jukes ◽  
Richard Whalley
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Skin Friction ◽  
Control Strategies ◽  
Travelling Wave ◽  
Friction Reduction ◽  
Plasma Actuators ◽  
Control Technique ◽  
Boundary Layer Control ◽  
Layer Control

This paper reviews turbulent boundary-layer control strategies for skin-friction reduction of aerodynamic bodies. The focus is placed on the drag-reduction mechanisms by two flow control techniques—spanwise oscillation and spanwise travelling wave, which were demonstrated to give up to 45 per cent skin-friction reductions. We show that these techniques can be implemented by dielectric-barrier discharge plasma actuators, which are electric devices that do not require any moving parts or complicated ducting. The experimental results show different modifications to the near-wall structures depending on the control technique.

Application of Air Microblowing Through a Porous Wall for Skin Friction Reduction on a Flat Plate

2010 ◽  
Vol 5 (3) ◽  
pp. 38-46
Author(s):  
Vladimir I. Kornilov ◽  
Andrey V. Boiko
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Skin Friction ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Porous Wall ◽  
Friction Reduction ◽  
Local Skin ◽  
Skin Friction Reduction

The effect of air microblowing through a porous wall on the properties of a turbulent boundary layer formed on a flat plate in an incompressible flow is studied experimentally. The Reynolds number based on the momentum thickness of the boundary layer in front of the porous insert is 3 900. The mass flow rate of the blowing air per unit area was varied within Q = 0−0.0488 кg/s/m2 . A consistent decrease in local skin friction, reaching up to 45−47 %, is observed to occur at the maximal blowing air mass flow rate studied.

Physics and control of wall turbulence for drag reduction

2011 ◽  
Vol 369 (1940) ◽  
pp. 1396-1411 ◽  
Author(s):  
John Kim
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Skin Friction ◽  
Linear Analysis ◽  
Wall Turbulence ◽  
Boundary Layer Control ◽  
Control Input ◽  
Friction Drag ◽  
Nonlinear Simulations ◽  
Layer Control

Turbulence physics responsible for high skin-friction drag in turbulent boundary layers is first reviewed. A self-sustaining process of near-wall turbulence structures is then discussed from the perspective of controlling this process for the purpose of skin-friction drag reduction. After recognizing that key parts of this self-sustaining process are linear, a linear systems approach to boundary-layer control is discussed. It is shown that singular-value decomposition analysis of the linear system allows us to examine different approaches to boundary-layer control without carrying out the expensive nonlinear simulations. Results from the linear analysis are consistent with those observed in full nonlinear simulations, thus demonstrating the validity of the linear analysis. Finally, fundamental performance limit expected of optimal control input is discussed.

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