Estimation of Aerodynamic Coefficients in a Small Subsonic Wind Tunnel
Abstract
To apply the experimental data measured in a wind tunnel for a scaled aircraft to a free-flying model, conditions of dynamical similarity must be met or scaling procedures introduced. The scaling methods should correct the wind tunnel data regarding model support, wall interference, and lower Reynolds number. To include the necessary corrections, the current scaling techniques use computational fluid dynamics (CFD) in combination with measurements in cryogenic wind tunnels. There are a few methods that enable preliminary calculations of typical corrections considering specific measurement conditions and volume limitation of test section. The purpose of this paper is to present one possible approach to estimating corrections due to sting interference and difference in Reynolds number between the real airplane in cruise regime and its 1:100 model in the small wind tunnel AT-1. The analysis gives results for correction of axial and normal force coefficients. The results of this analysis indicate that the Reynolds number effects and the problem of installation of internal force balance are quite large. Therefore, the wind tunnel AT-1 has limited usage for aerodynamic coefficient determination of transport airplanes, like Dash 8 Q400 analyzed in this paper.
References
K. Pettersson and A. Rizzi, "Aerodynamic Scaling to Free Flight Conditions: Past and Present," Progress in Aerospace Sciences, vol. 44, no. 4, pp. 295-313, 2008.
J. B. Barlow, W. H. Rae and A. Pope, Low-Speed Wind Tunnel Testing, New York: John Wiley &Sons, 1999.
B. Horsten, "Low-Speed Model Support Interference - Elements of an Expert System," Delft University of Technology, Delft, 2009.
D. M. Bushnell, "Scaling: Wind Tunnel to Flight," Annual Review of Fluid Mechanics, vol. 38, pp. 111-128, 2006.
L. W. Traub, "Drag Extrapolation to Higher Reynolds Number," Journal of Aircraft, vol. 46, no. 4, pp. 1458-1461, 2009.
M. Mirzaei, M. H. Karimi and M. A. Vaziri, "An Investigation of a Tactical Cargo Aircraft Aft Body Drag Reduction Based on CFD Analysis and Wind Tunnel Tests," Aerospace Science and Technology, vol. 23, no. 1, pp. 263-269, 2012.
K. Pettersson and A. Rizzi, "Reynolds Number Effects Identified with CFD Methods Compared to Semi-Empirical Methods," in 25th International Congress of the Aeronautical Sciences (ICAS 2006), Hamburg, Germany, 2006.
M. Maina, N. Corby, E. L. Crocker, P. J. Hammond and P. W. C. Wong, "A feasiblity study on designing model support systems for a blended wing body configuration in a transonic wind tunnel," Aeronautical Journal, vol. 110, no. 1103, p. 53.62, 2006.
R. Rudnik and E. Germain, "Reynolds Number Scaling Effects on the European High-Lift Project Configurations," Journal of Aircraft, vol. 46, no. 4, pp. 1140-1151, 2009.
B. Pamadi, "Performance, Stability, Dynamics, and Control of Airplanes," AIAA, Reston, Virginia, 1998.
S. Janković, Aircraft Flight Mechanics, Zagreb: Faculty of Mechanical Engineering and Naval Architecture, 2002.
A. A. Лебедев, "Динамика полета: Машиностроение," Москва, 1973.
Copyright (c) 2018 Karolina Krajček Nikolić, Anita Domitrović, Slobodan Janković
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
