Experimental Investigation of Reverse Flow over Sharp and Blunt Trailing Edge Airfoils

2013 ◽  
Author(s):  
Andrew H. Lind ◽  
Jonathan N. Lefebvre ◽  
Anya R. Jones
Keyword(s):  
Experimental Investigation ◽  
Reverse Flow ◽  
Trailing Edge ◽  
Blunt Trailing Edge

Experimental Investigation of the Vortex Shedding in the Wake of Oblique and Blunt Trailing Edge Hydrofoils Using PIV-POD Method

2010 ◽  
Author(s):  
Amirreza Zobeiri ◽  
Philippe Ausoni ◽  
Franc¸ois Avellan ◽  
Mohamed Farhat
Keyword(s):  
Experimental Investigation ◽  
Phase Shift ◽  
Vortex Shedding ◽  
High Speed ◽  
Flow Induced Vibration ◽  
Trailing Edge ◽  
Blunt Trailing Edge ◽  
Vortex Induced Vibrations ◽  
Image Velocimetry ◽  
High Reynolds

This paper presents an experimental investigation of the vortex shedding in the wake of blunt and oblique trailing edge hydrofoils at high Reynolds number, Re = 5 105 − 2.9 106. The velocity field in the wake is surveyed with the help of Particle-Image-Velocimetry, PIV, using Proper-Orthogonal-Decomposition, POD. Besides, flow induced vibration measurements and high-speed visualization are performed. The high-speed visualization clearly shows that the oblique trailing edge leads to a spatial phase shift of the upper and lower vortices at their generation stage, resulting their partial cancellation. For the oblique trailing edge geometry and in comparison with the blunt one, the vortex-induced vibrations are significantly reduced. Moreover, PIV data reveals a lower vorticity for the oblique trailing edge. The phase shift between upper and lower vortices, introduced by the oblique truncation of the trailing edge, is found to vanish in the far wake, where alternate shedding is recovered as observed with the blunt trailing edge. The phase shift generated by the oblique trailing edge and the resulting partial cancellation of the vortices is believed to be the main reason of the vibration reduction.

Time-Averaged Aerodynamics of Sharp and Blunt Trailing-Edge Static Airfoils in Reverse Flow

AIAA Journal ◽  
2014 ◽  
Vol 52 (12) ◽  
pp. 2751-2764 ◽  
Author(s):  
Andrew H. Lind ◽  
Jonathan N. Lefebvre ◽  
Anya R. Jones
Keyword(s):  
Reverse Flow ◽  
Trailing Edge ◽  
Blunt Trailing Edge

An Experimental Investigation of a Low-Speed Circulation-Controlled Aerofoil

1968 ◽  
Vol 19 (2) ◽  
pp. 170-182 ◽  
Author(s):  
R. J. Kind ◽  
D. J. Maull
Keyword(s):  
Experimental Investigation ◽  
Angle Of Incidence ◽  
Pitching Moment ◽  
Two Dimensional ◽  
Trailing Edge ◽  
Low Speed ◽  
Momentum Coefficient ◽  
Blunt Trailing Edge ◽  
Elliptic Section ◽  
Jet Blowing

SummaryExperiments performed on a low-speed circulation-controlled aerofoil are described. The aerofoil was of elliptic section with the circulation controlled by means of a jet blowing around the blunt trailing edge. Results for the lift, drag and pitching moment on the aerofoil are presented as functions of the blowing momentum coefficient and the angle of incidence. The results are for a two-dimensional aerofoil. Possible applications of this type of aerofoil are briefly discussed.

Experimental investigation of a simulated compressor airfoil trailing-edge flowfield

AIAA Journal ◽  
1985 ◽  
Vol 23 (5) ◽  
pp. 768-775 ◽  
Author(s):  
Robert W. Paterson ◽  
Harris D. Weingold
Keyword(s):  
Experimental Investigation ◽  
Trailing Edge

Analysis of Blunt Trailing Edge Airfoils

2003 ◽  
Author(s):  
K. J. Standish ◽  
C. P. van Dam
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Navier Stokes ◽  
Computational Techniques ◽  
Wind Turbine Blades ◽  
Trailing Edge ◽  
Blunt Trailing Edge ◽  
Large Wind ◽  
Structural Volume

The adoption of blunt trailing edge airfoils for the inner regions of large wind turbine blades has been proposed. Blunt trailing edge airfoils would not only provide increased structural volume, but have also been found to improve the lift characteristics of airfoils and therefore allow for section shapes with a greater maximum thickness. Limited experimental data makes it difficult for wind turbine designers to consider and conduct tradeoff studies using these section shapes. This lack of experimental data precipitated the present analysis of blunt trailing edge airfoils using computational fluid dynamics. Several computational techniques are applied including a viscous/inviscid interaction method and several Reynolds-averaged Navier-Stokes methods.

Separation in oscillating laminar boundary-layer flows

1971 ◽  
Vol 47 (1) ◽  
pp. 21-31 ◽  
Author(s):  
R. A. Despard ◽  
J. A. Miller
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Reverse Flow ◽  
Oscillation Amplitude ◽  
Hot Wire ◽  
Boundary Layer Flows ◽  
Laminar Boundary Layers ◽  
History Of

The results of an experimental investigation of separation in oscillating laminar boundary layers is reported. Instantaneous velocity profiles obtained with multiple hot-wire anemometer arrays reveal that the onset of wake formation is preceded by the initial vanishing of shear at the wall, or reverse flow, throughout the entire cycle of oscillation. Correlation of the experimental data indicates that the frequency, Reynolds number and dynamic history of the boundary layer are the dominant parameters and oscillation amplitude has a negligible effect on separation-point displacement.

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