The NASA Langley laminar flow control airfoil experiment

Harvey, W. D.; Pride, J. D.

doi:10.2514/6.1982-567

Cited by 19 publications

(6 citation statements)

References 4 publications

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“…The flow is governed by the non similar boundary-layer equation (1) with boundary conditions (2) given in the Gortler variables (3) Then the velocity components u and v in terms of the new variables are u=U.J Tl (4) (5) where the suction and pressure gradient functions r and ~ respectively are defined as (6) (7) Note that negative r indicates suction, while negative ~ indicates unfavorable pressure gradient. If both the suction and pressure gradient functions are constant (equal to ro and ~o respectively), then f (~,Tl) is a function of Tl only and we have a similar boundary-layer profile governed by (9) where the condition ro==constant demands that Vw be proportional to UelffE:,.…”

Section: The Mean Flowmentioning

confidence: 99%

Effect of suction on controlling the secondary instability of boundary layers

El-Hady

1991

Physics of Fluids A: Fluid Dynamics

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The effect of suction on controlling the three-dimensional secondary instability is investigated for a boundary layer with pressure gradient in the presence of small but finite amplitude Tollmien-Schlichting wave. The focus is on principal parametric resonance responsible for strong growth of subharmonics in low disturbance environment. Calculations are presented for the effect of suction on the onset and amplification of the secondary instability in Blasius and Falkner-Skan flows, as well as its effect on controlling the production of the vortical structure.

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Section: The Mean Flowmentioning

confidence: 99%

Effect of suction on controlling the secondary instability of boundary layers

El-Hady

1991

Physics of Fluids A: Fluid Dynamics

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“…More recently there have been several experiments designed to determine whether the Gortler mechanism is significant on the curved part of modern laminar flow wings; see for example Pfenninger et al (1980), Harvey and Pride (1982), Allison and Dagenhart (1987). In particular much work has been done at NASA Langley on a wing with a significant region of concave curvature on the underside of the wing just beyond the leading edge.…”

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confidence: 99%

Görtler vortices in growing boundary layers: The leading edge receptivity problem, linear growth and the nonlinear breakdown stage

1990

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Görtler vortices are thought to be the cause of transition in many fluid flows of practical importance. In this paper a review of the different stages of vortex growth is given. In the linear regime nonparallel effects completely govern this growth and parallel flow theories do not capture the essential features of the development of the vortices. A detailed comparison between the parallel and nonparallel theories is given and it is shown that at small vortex wavelengths the parallel flow theories have some validity; otherwise nonparallel effects are dominant. New results for the receptivity problem for Gortler vortices are given; in particular vortices induced by free‐stream perturbations impinging on the leading edge of the wall are considered. It is found that the most dangerous mode of this type can be isolated and its neutral curve is determined. This curve agrees very closely with the available experimental data. A discussion of the different regimes of growth of nonlinear vortices is also given. Again it is shown that, unless the vortex wavelength is small, nonparallel effects are dominant. Some new results for nonlinear vortices of O(l) wavelengths are given and compared with experimental observations. The agreement between theory and experiment is shown to be excellent up to the point where unsteady effects become important. For small wavelength vortices the nonlinear regime is of particular interest since a strongly nonlinear theory can be developed there. Here the vortices can be large enough to drive the mean state which then adjusts itself to make all modes neutral. The breakdown of this nonlinear state into a three‐dimensional time dependent flow is also discussed.

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“…The growth of Taylor-G6rtler vortices in incompressible boundary layers has received a lot of attention in recent years due to its relevance to Laminar Flow Control (see for example Harvey and Pride [1]). The original calculation by G6rtler [2] showed that Taylor's [3] instability mechanism which occurs for curved flows also operates in boundary-layer flows.…”

Section: Introductionmentioning

confidence: 99%

The growth of Görtler vortices in compressible boundary layers

Hall

Malik

1989

J Eng Math

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Abstract. The linear instability of G6rtler vortices in compressible boundary layers is considered. Using asymptotic methods in the high-wavenumber regime, it is shown that a growth-rate estimate can be found by solving a sequence of linear equations. The growth rate obtained in this way takes non-parallel effects into account and can be found much more easily than by ordinary differential equation eigenvalue calculations associated with parallel-flow theories.

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The NASA Langley laminar flow control airfoil experiment

Cited by 19 publications

References 4 publications

Effect of suction on controlling the secondary instability of boundary layers

Effect of suction on controlling the secondary instability of boundary layers

Görtler vortices in growing boundary layers: The leading edge receptivity problem, linear growth and the nonlinear breakdown stage

The growth of Görtler vortices in compressible boundary layers

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