Volume 20, Issue 8 (August 2020)                   Modares Mechanical Engineering 2020, 20(8): 2101-2112 | Back to browse issues page

XML Persian Abstract Print

Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

Maleki G, Tabatabaeian S, Soltani M, Davari A. Enhancement of the Accuracy of Experimental Drag Coefficient Calculation of an Airfoil by Including the Turbulence Velocity Terms in the Wake Region. Modares Mechanical Engineering 2020; 20 (8) :2101-2112
URL: http://mme.modares.ac.ir/article-15-35184-en.html
1- Department of Aerospace Engineering, Science & Research Branch, Islamic Azad University, Tehran, Iran
2- Aerospace Engineering Faculty, Sharif University of Technology, Tehran, Iran , msoltani@sharif.edu
Abstract:   (1855 Views)
In the present study, the instantaneous velocity profile behind an airfoil at two different Reynolds numbers has been measured experimentally. Data are used to study the wake profile and the corresponding drag coefficient force of the airfoil in different conditions. In the conventional and common methods for calculation of the drag force coefficient through the velocity measurement behind an airfoil, turbulence velocity terms of the momentum equation are ignored. However at moderate to high angles of attack where the flow becomes turbulent and separation occurs, the nature of the flow becomes three dimensional and disregarding the components of the fluctuation of velocity (in three dimensions) in calculation of the drag coefficient of airfoil may result in erroneous information. In the present study, in order to increase the accuracy of the experimental drag coefficient of the airfoil for moderate to high angles of attack, turbulence velocity terms in experimental drag coefficient calculation are considered and this causes an acceptable compatibility between experimental and numerical results whereas for low angles of attack, disregarding the effects of turbulence velocity terms in experimental drag coefficient calculation will improve the accuracy of the experimental drag coefficient and a desired compatibility between experimental and numerical data will be established.
Full-Text [PDF 1271 kb]   (1038 Downloads)    
Article Type: Original Research | Subject: Computational Fluid Dynamic (CFD)
Received: 2019/07/26 | Accepted: 2020/05/5 | Published: 2020/08/15

1. Betz A. A method for the direct determination of wing section drag [Internet]. United States: NTRS; 1925 [Unknown Cited]. Available from: https://ntrs.nasa.gov/search.jsp?R=19930090720 [Link]
2. Jones BM. Measurement of profile drag by the pitot traverse method. London: H.M. Stationery Office; 1936. [Link]
3. Taylor GI. The determination of drag by the pitot travers method. London: H.M. Stationery Office; 1937. [Link]
4. Bollay W. Determination of profile drag from measurements in the wake of a body. Journal Aeronautical Sciences. 1938;5(6):245-248. [Link] [DOI:10.2514/8.597]
5. Goett HJ. Experimental investigation of the momentum method for determining profile drag [Internet]. United States: NTRS; 1939 [Unknown Cited]. Available from: https://ntrs.nasa.gov/search.jsp?R=19930091734 [Link]
6. Takahashi TT. On the decomposition of drag from wake survey measurements. 35th Aerospace Sciences Meeting and Exhibit, 6-9 Junuary 1997, Reno, United States. Reno: AIAA; 1997; [Link] [DOI:10.2514/6.1997-717]
7. Antonia RA, Rajagopalan S. Determination of drag of a circular cylinder. AIAA Journal. 1990;28(10):1833-1834. [Link] [DOI:10.2514/3.10485]
8. Chao DD, Van Dam CP. Airfoil drag prediction and decomposition. Journal of Aircraft. 1999;36(4):675-681. [Link] [DOI:10.2514/2.2510]
9. Van Dam CP. Recent experience with different methods of drag prediction, Progress in Aerospace Sciences. 1999;35(8):751-798. [Link] [DOI:10.1016/S0376-0421(99)00009-3]
10. Goldstein S. A note on the measurement of total head and static pressure in a turbulent stream. Royal Society. 1936;155(886):570-575. [Link] [DOI:10.1098/rspa.1936.0120]
11. Barlow JB, Rae WH, Pope A. Low-speed wind tunnel testing. Hoboken: John Wiley & Sons; 1984. [Link]
12. Soltani MR., Rasi F, Sedighi M, Bakhshalipour A. An experimental investigation of time lag in pressure-measuring systems. Ankara International Aerospace Conference (AIAC), Unknown Date & Location & Publisher of Conference. 2005. [Link]
13. Lu B, Bragg MB. Experimental investigation of the wake-survey method for a bluff body with a highly turbulent wake. 20th AIAA Applied Aerodynamics Conference, 24-26 June 2002, St. Louis, United States. Reno: AIAA; 2002. [Link] [DOI:10.2514/6.2002-3060]
14. Lu B, Bragg BM. Airfoil drag measurement with simulated leading-edge ice using the wake survey method. 41st Aerospace Sciences Meeting and Exhibit. 6-9 January 2003, Reno, United States. Reno: AIAA; 2003. [Link] [DOI:10.2514/6.2003-1094]
15. Anderson JD. Fundamentals of aerodynamics. New York: McGraw-Hill; 2001. [Link]

Add your comments about this article : Your username or Email:

Send email to the article author

Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.