Frequency-Domain Decoupling-Correction Method for Wind Tunnel Strain-Gauge Balance

2013 ◽  
Vol 62 (9) ◽  
pp. 2596-2608 ◽  
Author(s):  
Shuang-Long Yang ◽  
Ke-Jun Xu
Keyword(s):  
Wind Tunnel ◽  
Frequency Domain ◽  
Strain Gauge ◽  
Correction Method ◽  
Tunnel Strain

An Improved Correction Method for Sound Source Drift in A Jet Flow and Its Application to A Wind Tunnel Measurement

2015 ◽  
Vol 101 (3) ◽  
pp. 642-649 ◽  
Author(s):  
Yigang Wang ◽  
Jiashun Yang ◽  
Qing Jia ◽  
Zhigang Yang ◽  
Zhe Shen
Keyword(s):  
Wind Tunnel ◽  
Sound Source ◽  
Jet Flow ◽  
Correction Method ◽  
Wind Tunnel Measurement

Static and Dynamic Analysis of a NACA 0021 Airfoil Section at Low Reynolds Numbers: Drag and Moment Coefficients

2019 ◽  
Author(s):  
David Holst ◽  
Francesco Balduzzi ◽  
Alessandro Bianchini ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Wind Turbines ◽  
Reynolds Numbers ◽  
Correction Method ◽  
Hysteresis Cycle ◽  
Low Reynolds Numbers ◽  
Static And Dynamic Analysis ◽  
Wide Range ◽  
Low Reynolds

Abstract Wind industry needs high quality airfoil data for a range of the angle of attack (AoA) much wider than that often provided by the technical literature, which often lacks data i.e. in deep- and post-stall region. Especially in case of vertical axis wind turbines (VAWTs), the blades operate at very large AoAs, which exceed the range of typical aviation application. In a previous study, some of the authors analyzed the trend of the lift coefficient of a NACA 0021 airfoil, using the suggestions provided by detailed CFD analyses to correct experimental data at low Reynolds numbers collected in an open-jet tunnel. In the present study, the correction method is extended in order to analyze even the drag and moment coefficients over a wide range of AoAs for two different Reynolds numbers (Re = 140k and Re = 180k) of particular interest for small wind turbines. The utility of these data is again specifically high in case of VAWTs, in which both the drag and the moment coefficient largely contribute to the torque. The investigation involves tunnel data regarding both static polars and dynamic sinusoidal pitching movements at multiple reduced frequencies. Concerning the numerical simulations, two different computational domains were considered, i.e. the full wind tunnel and the open field. Once experimental data have been purged by the influence of the wind tunnel by means of the proposed correction method, they were compared to existing data for similar Reynolds both for the NACA0021 and for similar airfoils. By doing so, some differences in the static stall angle and the extent of the hysteresis cycle are discussed. Overall, the present paper provides the scientific community with detailed analysis of low-Reynolds NACA 0021 data in multiple variations, which may enable, inter alia, a more effective VAWT design in the near future.

Extensions to Maskell’s theory for blockage effects on bluff bodies in a closed wind tunnel

2001 ◽  
Vol 105 (1050) ◽  
pp. 409-418 ◽  
Author(s):  
J. E. Hackett ◽  
K. R. Cooper
Keyword(s):  
Wind Tunnel ◽  
Flat Plate ◽  
Correction Method ◽  
The Other ◽  
Bluff Bodies ◽  
Low Speed ◽  
Test Conditions ◽  
Lift And Drag ◽  
Low Speed Wind Tunnel

Abstract Extensions to Maskell’s original correction method, developed over several years, are consolidated and designated ‘Maskell III’. The procedures were applied to dedicated tests on a family of flat-plate wing models in a small, low-speed wind tunnel at NRC. Test conditions included angles of attack from -10° to 110° and models of up to 16% of tunnel area. Off-centre tests were included with model-to-wall distances down to 0.72 chords. Corrected lift and drag data correlated well between models of different sizes and at different offsets from the tunnel centreline. Comparisons are made with corrections using the pressure-signature and two-variable methods, emphasising post-stall conditions. These showed that the ‘Maskell III’ procedures, which require minimal input, correlated as well as the other methods for most model sizes and positions in the tunnel.

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