Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-27T15:26:24.389Z Has data issue: false hasContentIssue false

A demonstration of the effect of the testing environment on unsteady aerodynamics experiments

Published online by Cambridge University Press:  04 July 2016

R. B. Green
Affiliation:
Department of Aerospace Engineering, University of Glasgow
R. A. McD. Galbraith
Affiliation:
Department of Aerospace Engineering, University of Glasgow

Abstract

The effects of windtunnel constraint during low speed unsteady aerodynamic experiments are assessed by comparing the data from two Naca 0015 models, one with a chord length of half the other. Ramp-up and ramp-down tests are considered, to distinguish between the effects of constraint upon separation and attachment. The unsteady separation process measured in terms of the normal force, pitching moment and stall vortex convection speed, is virtually unaffected by the difference in constraint between the two models, whereas the attachment process, assessed in terms of the normal force response and attachment behaviour, is sensitive to the size of the model.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1994 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Engineering Sciences Data Unit (ESDU), Aerodynamics Sub-series, 13, 1985, Item numbers 76028, 80024.Google Scholar
2. McCroskey, W.J., Carr, L.W. and McAlister, K.W. Dynamic stall experiments on oscillating aerofoils, A1AA J, 1976, 14, p 57.Google Scholar
3. Green, R.B., Galbraith, R.A.McD. and Niven, A.J. Measurements of the dynamic stall vortex convection speed, Aeronaut J, 1992, 96, (918), pp 319325.Google Scholar
4. Lorber, P.F. and Carta, F.O. Unsteady Stall Penetration Experiments at High Reynolds Number, AFOSR TR-87-1202, UTRCR87-956939-3, 1987.Google Scholar
5. Green, R.B., Galbraith, R.A.McD. and Niven, A.J. The Convection Speed of the Dynamic Stall Vortex, AFOSR-89-0397 A, University of Glasgow Aero Rept 9202.Google Scholar
6. Niven, A.J., Galbraith, R.A.McD. and Herring, D.G.F. Analysis of reattachment during ramp down tests, Vertica, 1989, 13, p 187.Google Scholar
7. Niven, A.J. and Galbraith, R.A.McD. Experiments on the establishment of fully attached flow from the fully stalled condition during ramp-down motions, Presented at 17th ICAS Congress, Stockholm, Sweden, 1990.Google Scholar
8. Koopman, G.H. The vortex wakes of vibrating cylinders at low Reynolds numbers, J Fluid Mech, 1967, 28, p 501.Google Scholar
9. Green, R.B. and Galbraith, R.A.McD. Phenomena observed during aerofoil ramp-down motions from the fully separated state. To be published.Google Scholar
10. Moss, G.F. and Murdin, P.M. Two-dimensional low-speed tunnel tests on the Naca 0012 section including measurements made during pitch oscillations at the stall, ARC CP 1145, 1971.Google Scholar
11. Ahmed, S. and Chandrasekhara, M.S. Reattachment Studies of an Oscillating Airfoil Dynamic Stall Flowfield, AIAA 91-3225, 9th Applied Aerodynamics Conference, Baltimore, MD, 1991.Google Scholar