Effects of Leading-Edge Separation on Thin Wings in Two-Dimensional Incompressible Flow

1957 ◽  
Vol 24 (8) ◽  
pp. 597-604 ◽  
Author(s):  
L. F. CRABTREE
Keyword(s):  
Incompressible Flow ◽  
Leading Edge ◽  
Two Dimensional ◽  
Edge Separation

Two-dimensional unsteady leading-edge separation on a pitching airfoil

AIAA Journal ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 673-681 ◽  
Author(s):  
P. Ghosh Choudhuri ◽  
D. D. Knight ◽  
M. R. Visbal
Keyword(s):  
Leading Edge ◽  
Two Dimensional ◽  
Pitching Airfoil ◽  
Edge Separation

A Theoretical Approach to the Aerodynamically Significant Properties of Roughness from Insects

1960 ◽  
Vol 11 (2) ◽  
pp. 171-194 ◽  
Author(s):  
W. S. Coleman
Keyword(s):  
Incompressible Flow ◽  
Theoretical Approach ◽  
Leading Edge ◽  
Critical Conditions ◽  
Two Dimensional ◽  
Edge Zone ◽  
Good Agreement

SummaryIn Reference 3, attention is drawn to the difficulties of measuring the streamwise extent of the roughness from insects. The present paper deals with the problem theoretically for an aerofoil in two-dimensional, incompressible flow. A tentative approach to the determination of effective excrescence height downstream of the leading-edge zone is also advanced. The application of these investigations, in conjunction with the analysis from Ref. 3 regarding the critical conditions for premature transition, leads to estimates of the amount of significant roughness which are in good agreement with flight observation.

Comments on Milgram: “Calculation of Attached or Partially Separated Flow Around Airfoil Sections”

1978 ◽  
Vol 22 (01) ◽  
pp. 64-65
Author(s):  
Fabio R. Goldschmied
Keyword(s):  
Experimental Verification ◽  
A Priori ◽  
Separated Flow ◽  
Leading Edge ◽  
Suction Side ◽  
Separated Flows ◽  
Two Dimensional ◽  
The Subject ◽  
Edge Separation ◽  
Theoretical Results

The title paper presents a relatively unified potential flow theory for attached and partially separated (trailing-edge separation) two-dimensional, incompressible airfoil sections. The partially separated flows are characterized by nonreattaching flow separation from a point on the suction side of the airfoil downstream from the leading edge; it is required that the location of this separation point and the corresponding separation pressure be specified a priori. Figures 5 and 6 of the subject paper present the test data and the theoretical results for the NACA 63–018 airfoil at 15- and 18-deg angle of attack, respectively, as the only experimental verification for partially separated flows.

Oscillating Slender Wings with Leading-Edge Separation

1966 ◽  
Vol 17 (4) ◽  
pp. 311-331 ◽  
Author(s):  
D. G. Randall
Keyword(s):  
Cross Sections ◽  
Reasonable Agreement ◽  
Theoretical Study ◽  
Leading Edge ◽  
Two Dimensional ◽  
Harmonic Oscillations ◽  
Delta Wings ◽  
Reduced Frequency ◽  
Straight Lines ◽  
Edge Separation

SummaryA theoretical study is made of the aerodynamics of wings executing simple harmonic oscillations. The wings considered are slender and infinite-simally thin; they may have curved leading edges and be cambered, but their cross sections must be straight lines. The value of the reduced frequency is assumed to be such that the flow is governed by the two-dimensional Laplace equation.Leading-edge separation is simulated by a line vortex joined to the leading edge by a cut. The strength and position of the vortex and the values of the generalised forces can be determined by the theory. Results have been calculated for flat delta wings and a flat gothic wing; they are in reasonable agreement with experiment.

Progress towards a theory of jet-flap thrust recovery

1984 ◽  
Vol 141 ◽  
pp. 347-364 ◽  
Author(s):  
P. M. Bevilaqua ◽  
E. F. Schum ◽  
C. J. Woan
Keyword(s):  
Interaction Analysis ◽  
Separation Bubble ◽  
Leading Edge ◽  
Two Dimensional ◽  
Thrust Coefficient ◽  
Large Loss ◽  
Jet Mixing ◽  
Small Loss ◽  
Edge Separation ◽  
Loss Of Thrust

A combination of analysis and testing has been utilized to develop a theory of jet-flap thrust recovery at the low speeds and high deflection angles characteristic of V/STOL lift systems. The contribution of jet mixing to the loss of thrust recovery has been computed with a viscid/inviscid interaction analysis. The results of this computation are compared to surface pressure and wake survey measurements made with a two-dimensional jet-flapped airfoil model. It is concluded that the jet-mixing drag causes a small loss of recovery at small values of the jet-thrust coefficient and deflect, an angle. However, at larger values of either jet parameter, the mainstream separates from the airfoil, producing a large loss of recovery. The loss increases suddenly, since it is due to bursting of the leading-edge separation bubble.

Rotational temperature imaging of a leading-edge separation in hypervelocity flow

2019 ◽  
Author(s):  
Laurent M. Le Page ◽  
Matthew Barrett ◽  
Sean O’Byrne ◽  
Sudhir L. Gai
Keyword(s):  
Rotational Temperature ◽  
Leading Edge ◽  
Temperature Imaging ◽  
Edge Separation

Three-Dimensional and Rotational Aerodynamics on the NREL Phase VI Wind Turbine Blade

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Separated Flow ◽  
Leading Edge ◽  
Wind Turbine Blade ◽  
Trailing Edge ◽  
Rotating Blade ◽  
Nrel Phase Vi ◽  
Edge Separation

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.

Scalars convected by a two-dimensional incompressible flow

2001 ◽  
Vol 55 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Diego Cordoba ◽  
Charles Fefferman
Keyword(s):  
Incompressible Flow ◽  
Two Dimensional
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