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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
Enhancement of the Accuracy of Experimental Drag Coefficient Calculation of an Airfoil by Including the Turbulence Velocity Terms in the Wake Region
Gh. Maleki1 , S. Tabatabaeian1 , M.R. Soltani * 2, A. Davari1
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:   (3386 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.
Keywords: Wind Turbine, Wake Region, Drag Coefficient, Reynolds Number, Pressure Rake, Turbulence Velocity Terms
Full-Text [PDF 1271 kb]   (4555 Downloads)    
Article Type: Original Research | Subject: Computational Fluid Dynamic (CFD)
Received: 2019/07/26 | Accepted: 2020/05/5 | Published: 2020/08/15
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