0
Research Papers: Fundamental Issues and Canonical Flows

Prediction of Dynamic Stall Onset for Oscillatory Low-Speed Airfoils

[+] Author and Article Information
W. Sheng

Department of Aerospace Engineering, University of Glasgow, Glasgow G12 8QQ, UKwsheng@aero.gla.ac.uk

R. A. Galbraith

Department of Aerospace Engineering, University of Glasgow, Glasgow G12 8QQ, UKr.a.m.galbraith@aero.gla.ac.uk

F. N. Coton

Department of Aerospace Engineering, University of Glasgow, Glasgow G12 8QQ, UKf.coton@aero.gla.ac.uk

J. Fluids Eng 130(10), 101204 (Sep 04, 2008) (8 pages) doi:10.1115/1.2969450 History: Received October 05, 2007; Revised July 01, 2008; Published September 04, 2008

This research presents some common features of oscillatory airfoils, and the method for indicating dynamic stall onset for the unsteady process. Under deep stall conditions, the stall-onset angle in oscillation is independent of the mean angle of the oscillatory motion, and by combining the reduced frequency and the amplitude of the oscillatory motion, the equivalent reduced pitch rate is an analog of this motion to the constant reduced pitch rate of the ramp-up motion. By correlating with the measured data, and with the ramp-up results, the equivalent reduced pitch rate can be defined as a representation for the oscillatory motion. Accordingly, the triple-parameter problem of an oscillation (mean angle, reduced frequency, and amplitude) degrades into the single-parameter problem (equivalent reduced pitch rate). Based on these foundations, an extension of the stall-onset criterion is then made for oscillatory airfoils: a method of extracting the stall-onset parameters directly from oscillatory test data, and an indication of stall onset for the oscillatory airfoils. The results from the new proposed method have shown the consistency with the data of Glasgow University and the public data.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 5

Stall-onset angles against the reduced frequency, κ. (a) α=α0+10degsinωt (NACA 0012), (b) α=α0+10degsinωt (NACA 23012).

Grahic Jump Location
Figure 6

Stall-onset angle dependence on the equivalent reduced pitch rate, req. (a) NACA 0012, (b) NACA 23012, (c) GUVA 10.

Grahic Jump Location
Figure 7

Airfoil profiles studied in this research

Grahic Jump Location
Figure 8

Comparisons of dynamic stall-onset predictions. (a) NACA 0012, (b) NACA 23012, (c) GUVA 10.

Grahic Jump Location
Figure 9

Comparisons of predictions and experimental results for NACA 0012. (a) α=10deg+10degsinωt, κ=0.025, (b) α=10deg+10degsinωt, κ=0.099.

Grahic Jump Location
Figure 10

Comparisons of predictions and experimental results for NACA 23012. (a) α=10deg+10degsinωt, κ=0.051, (b) α=10deg10+degsinωt, κ=0.102.

Grahic Jump Location
Figure 11

Comparisons of predictions and experimental results for GUVA 10. (a) α=100deg+10degsinωt, κ=0.025, (b) α=10deg+10degsinωt, κ=0.100.

Grahic Jump Location
Figure 12

A validation for the public data

Grahic Jump Location
Figure 1

Comparison of static and unsteady forces including dynamic stall

Grahic Jump Location
Figure 2

Stall-onset incidences, αds, for the NACA 0012 oscillatory test (data taken from Galbraith (29))

Grahic Jump Location
Figure 3

A schematic for the stall-onset criterion (NACA 23012 ramp-up tests)

Grahic Jump Location
Figure 4

Stall-onset angles against mean angles of attack (NACA 0012, κ=0.025)

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In