Nonlinearity of the Aerodynamic Characteristics of NACA0012 Aerofoil at Low Reynolds Numbers

Ohtake, Tomohisa; Nakae, Yusuke; Motohashi, Tatsuo

doi:10.2322/jjsass.55.439

Cited by 92 publications

(66 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Despite the Reynolds number independence for pre-stall incidences reported by Jacobs and Sherman (1937), the results for the type I hydrofoils show effects for the lowest Reynolds number (Re c ¼ 0:2 Â 10 6 ) that suggest complex laminar flow effects. Ohtake et al (2007) and Selig et al (1995) show similar effects for two-dimensional NACA 4-digit sections for Re c up to 10 5 .…”

Section: Forcessupporting

confidence: 62%

Experimental study of the steady fluid–structure interaction of flexible hydrofoils

Zarruk

Brandner

Pearce

et al. 2014

Journal of Fluids and Structures

View full text Add to dashboard Cite

Section: Forcessupporting

confidence: 62%

Experimental study of the steady fluid–structure interaction of flexible hydrofoils

Zarruk

Brandner

Pearce

et al. 2014

Journal of Fluids and Structures

View full text Add to dashboard Cite

“…Streamlined airfoils, such as NACA 0012, exhibit nonlinear lift curves at low Reynolds numbers [20], whereas the Reynolds number has comparatively little effect on the aerodynamic characteristics of thin flat plates. In this study, the lift and drag forces and the pitching moment acting on wings are measured, and flow visualizations by smoke-wire and oil-film methods are performed in the wind tunnel.…”

mentioning

confidence: 99%

Aerodynamic Characteristics at Low Reynolds Number for Wings of Various Planforms

Okamoto

Azuma

2011

AIAA Journal

View full text Add to dashboard Cite

The aerodynamic characteristics of various wing planforms at low Reynolds numbers (about 1 10 4 ) were studied by conducting wind-tunnel tests. These low Reynolds numbers correspond to the flights of small creatures, such as insects. Elliptical, rectangular, and triangular planforms with various aspect ratios were used in this study, as well as a swept rectangular (parallelogram) wing with an aspect ratio of four. The wing sections of all models were thin rectangular airfoils. The aerodynamic forces (lift and drag) and the pitching moment acting on the wing were measured for a wide range of angles of attack (including the maximum of 90 deg). Nonlinear characteristics of the lift coefficient were obtained, even at low angles of attack for high-aspect-ratio wings, whereas a small lift slope and a large maximum lift coefficient were obtained for low-aspect-ratio wings. The drag and the pitching moment coefficients also exhibited nonlinear characteristics. The effect of the Reynolds number based on the wing chord was comparatively small, but a distinctive phenomenon in low-Reynolds-number flow was observed in flow visualization using oil-film and smoke-wire methods. Nomenclature AR = aspect ratio, b 2 =S a = lift slope b = span length c = chord length C = coefficient of forces and moment related to ( ) c = mean aerodynamic chord D = drag D i = induced drag D p = pressure drag D 0 = minimum drag e = span efficiency factor f = friction drag, frequency k = proportional constant defined by Eq. (9) K p = lift slope given by lifting surface theory K V = constant value given by leading-edge suction force K W = constant value about aspect ratio of wing in blockage correction factor L = lift M = pitching moment q, q c = dynamic pressure and its corrected value R = resultant aerodynamic force, L 2 D 2 p r = distance between feathering axis and center of gravity Re = Reynolds number based on c S = wing area St = Strouhal number S ts = cross-sectional area of test section t = wing thickness t= c = thickness ratio U = wind velocity = angle of attack = proportional constant defined by Eq. (9) x = chordwise distance between quarter-chord and measurement point z = thicknesswise model distance between measurement point and wing chord " = wall blockage correction factor = leading-edge sweep angle = air density Subscripts M = measured value max = maximum value min = minimum value ST = strut ts = test section

show abstract

“…Article in Advance / KANNER AND PERSSON for mesh 1 and mesh 2, respectively (no appreciable difference at this level). Experimental data from [27,29,37] Fig. 2b.…”

Section: B Results and Discussionmentioning

confidence: 99%

“…This Reynolds number range presents unique challenges to researchers who have to deal with separated, highly unsteady transitional flow. Though early wind-tunnel tests of the NACA0012 were plagued by inaccuracies [24], many recent experimental studies have used state-of-the-art pressure and force measurements, as well as flow visualization techniques (see, for instance, [25][26][27][28][29]). However, experimental studies will always be limited by the amount and type of data that can possibly be collected from such tests.…”

Section: Iles Simulation Of Naca0012 Airfoilmentioning

confidence: 99%

Validation of a High-Order Large-Eddy Simulation Solver Using a Vertical-Axis Wind Turbine

Kanner

Persson

2016

AIAA Journal

View full text Add to dashboard Cite

A high-order implicit large-eddy simulation method in two dimensions and three dimensions is used to simulate the aerodynamics of a NACA0012 airfoil over large angles of attack at low chord Reynolds numbers (Re 5000-50;000). The two-dimensional code is found to have adequate agreement with lift and drag experimental data for prestall angles of attack, whereas the three-dimensional code is validated over all angles of attack. The three-dimensional method is able to accurately predict the magnitude and frequency content of the lift and drag forces on the airfoil throughout the range of Reynolds numbers considered in this study. Further comparisons to experimental data are made, including particle image velocimetry vorticity data as well as dye-injection data. As an extension of this application, a section of a constant spinning straight-bladed vertical-axis wind turbine with two blades at a similar Reynolds number is subject to various inflow velocities in two dimensions and three dimensions. The pitch angle of the blades was also varied in order to take into account the uncertainties in the mounting angle of the blade in the experimental studies. As found previously, a small toe-out angle can increase the power absorption of the turbine on the order of 10%. The computed tangential forces as a function of the azimuthal angle agree much better with the experimental data at high tip-speed ratios as compared to other lower-fidelity analytical turbine codes.

show abstract

Nonlinearity of the Aerodynamic Characteristics of NACA0012 Aerofoil at Low Reynolds Numbers

Cited by 92 publications

References 4 publications

Experimental study of the steady fluid–structure interaction of flexible hydrofoils

Experimental study of the steady fluid–structure interaction of flexible hydrofoils

Aerodynamic Characteristics at Low Reynolds Number for Wings of Various Planforms

Validation of a High-Order Large-Eddy Simulation Solver Using a Vertical-Axis Wind Turbine

Contact Info

Product

Resources

About