Post-stall wind tunnel data for NACA 44XX series airfoil sections

Ostowari, C.; Naik, D. A.

doi:10.2172/5791328

Cited by 46 publications

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“…On the other hand, the two k-ε turbulence models seem to over-predict the drag coefficient, and have a large error of almost 52%. The lift and drag coefficients of the wind tunnel measurement with Re = 2.5 × 10 5 [24] are also shown in Figure 8. It can be seen that there is a significant trend in the lift coefficient as the angle of attack is varied from −5° and 12°.…”

Section: D Simulationmentioning

confidence: 99%

The Performance Test of Three Different Horizontal Axis Wind Turbine (HAWT) Blade Shapes Using Experimental and Numerical Methods

2013

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Three different horizontal axis wind turbine (HAWT) blade geometries with the same diameter of 0.72 m using the same NACA4418 airfoil profile have been investigated both experimentally and numerically. The first is an optimum (OPT) blade shape, obtained using improved blade element momentum (BEM) theory. A detailed description of the blade geometry is also given. The second is an untapered and optimum twist (UOT) blade with the same twist distributions as the OPT blade. The third blade is untapered and untwisted (UUT). Wind tunnel experiments were used to measure the power coefficients of these blades, and the results indicate that both the OPT and UOT blades perform with the same maximum power coefficient, C p = 0.428, but it is located at different tip speed ratio, λ = 4.92 for the OPT blade and λ = 4.32 for the UOT blade. The UUT blade has a maximum power coefficient of C p = 0.210 at λ = 3.86. After the tests, numerical simulations were performed using a full three-dimensional computational fluid dynamics (CFD) method using the k-ω SST turbulence model. It has been found that CFD predictions reproduce the most accurate model power coefficients. The good agreement between the measured and computed power coefficients of the three models strongly OPEN ACCESSEnergies 2013, 6 2785 suggest that accurate predictions of HAWT blade performance at full-scale conditions are also possible using the CFD method.

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Section: D Simulationmentioning

confidence: 99%

The Performance Test of Three Different Horizontal Axis Wind Turbine (HAWT) Blade Shapes Using Experimental and Numerical Methods

2013

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“…In the post-stall regime, however, only a sparse amount of wind tunnel test data is available. [47][48][49][50] In its current state-of-the-art, CFD is used as an ideal tool for design and optimization studies. In addition, it is used to better understand flow behavior around objects.…”

Section: A Airfoil Modelmentioning

confidence: 99%

Stall/Post-Stall Modeling of the Longitudinal Characteristics of a General Aviation Aircraft

Ananda

Selig

2016

AIAA Atmospheric Flight Mechanics Conference

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The high rate of accidents in general aviation due to pilot loss of control has necessitated the need to find better methods of training pilots. Pilot control and awareness in the stall/post-stall regime can be improved through the use of higher fidelity flight simulators. To create a high fidelity aerodynamic model in the stall/post-stall regime to be implemented in a flight simulator, both steady and unsteady aircraft characteristics need to be represented. In this paper, the detailed development of a steady-state general aviation aircraft stall/post-stall longitudinal aerodynamic model is described. The steady-state model uses a component buildup approach that uses strip theory to output the aerodynamic forces and moments of an aircraft. An integrated non-linear lifting-line theory approach is used to model the wing and horizontal tail. Longitudinal effects due to elevator deflections are also included. Validation studies are performed against static wind tunnel datasets for a typical single-engine low-wing general aviation aircraft design. Nomenclatureairfoil moment coefficient at quarter chord C M c/4 = surface moment coefficient at quarter chord (= M/ 1 2 ρV 2 ∞ S ref c) C N = surface normal force coefficient (= N/ 1 2 ρV 2 ∞ S ref ) C n = local normal-force coefficient per unit length * Graduate Student (Ph.D. Candidate), 104 S. Wright St., AIAA Student Member. anandak1@illinois.edu † Professor, 104 S. Wright St., AIAA Associate Fellow. m-selig@illinois.edu 1 of 25 American Institute of Aeronautics and Astronautics Downloaded by PURDUE UNIVERSITY on June 22, 2016 | http://arc.aiaa.org | AIAA Aviation d F = fuselage cross-section diameter D = drag D ind = induced drag k = corner radius l ref = reference length l F = fuselage length L = lift M = moment n P = number of lifting surface panels N = normal force r F = fuselage cross-section radius Re = Reynolds number based on mean aerodynamic chord (= V ∞ c/ν) S = lifting surface area S f = flap area S ref = reference area V ∞ = freestream velocity V F = fuselage volume w ind = velocity induced by shed vortices V rel = relative velocity w F = fuselage width x F = axial distance from fuselage nose x ac F = distance from nose to aerodynamic center of fuselage x c F = distance from nose to centroid of fuselage planform area x m F = distance from nose to centroid of fuselage pitching-moment reference center x P S , y P S , z P S = location of spanwise panel station points x LLT , y LLT , z LLT = location of lifting-line points Y = side force α ef f = effective angle of attack α geo = geometric angle of attack α ind = induced angle of attack β = sideslip angle δ f = flap deflection angle η = flap effectiveness correction factor η f use = fuselage crossflow drag proportionality factor Γ = circulation Γ 0 = circulation at center-span Γ LLT = circulation at the lifting-line points Γ SV = shed vortex circulation τ = flap effectiveness factor θ f = factor relating flap to chord ratio to flap effectiveness factor ν = kinematic viscosity ρ = density of air Subscripts c/4 = ...

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“…13 XFOIL is a panel code designed to model the effects of viscosity (to first order), and hence Reynolds number on various aerodynamic bodies. 14 The propellers evaluated in this work (made by APC) use the Clark Y airfoil section from 0 to 5% span, and the NACA 4412 for the remainder of the span.…”

Section: B Geometric and Aerodynamic Parameters 1 Aerodynamic Coeffmentioning

confidence: 99%

“…For angles of attack beyond stall, high-alpha data from Ostowari and Naik's wind tunnel testing is used. 13 The data covers the range of -10 to 110 degrees angle of attack. Studies on similar NACA sections provide the lift and drag data between -90 and -10 degrees.…”

Section: B Geometric and Aerodynamic Parameters 1 Aerodynamic Coeffmentioning

confidence: 99%

Blade Element Momentum Modeling of Low-Re Small UAS Electric Propulsion Systems

McCrink

Gregory

2015

33rd AIAA Applied Aerodynamics Conference

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A model for the propulsion system of a small-scale electric Unmanned Aircraft System (UAS) is presented. This model is based on a Blade Element Momentum (BEM) model of the propeller, with corrections for tip losses, Mach effects, three-dimensional flow components, and Reynolds scaling. Particular focus is placed on the estimation of scale effects not commonly encountered in the full-scale application of the BEM modeling method. Performance predictions are presented for geometries representative of several commercially available propellers. These predictions are then compared to experimental wind tunnel measurements of the propellers' performance. The experimental data supports the predictions of the proposed BEM model and points to the importance of scale effects on prediction of the overall system performance. Nomenclature a 0 = axial inflow correction factor a 1 = radial inflow correction factor A = test section area, m 2 B = number of blades c = chord, m C = faring area, m 2 C D = drag coefficient C L = lift coefficient , L pot C = lift coefficient from potential flow theoryPrandtl tip loss correction factor F = Prandtl tip loss correction factor I = current, A J = advance ratio K = local velocity correction factor L = lift, N M = Mach number n = rotation rate, rev/sec P = power, W AIAA Aviation 2 American Institute of Aeronautics and Astronautics q = dynamic pressure, Pa Q = torque, N-m r = radius, m Re = Reynolds number T = thrust, N V = velocity, m/s V l = local section velocity, m/s V r = radial velocity m/s V ∞ = freestream velocity, m/s V 1 = velocity across propeller disk, m/s V 2 = downstream velocity, m/s Greek  = angle of attack  = efficiency  = geometric angle of attack, rad  = Inflow angle  = density, kg/m 3 σ = propeller solidity  = tunnel correction factor  = rotation rate, rad/s

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Post-stall wind tunnel data for NACA 44XX series airfoil sections

Cited by 46 publications

References 0 publications

The Performance Test of Three Different Horizontal Axis Wind Turbine (HAWT) Blade Shapes Using Experimental and Numerical Methods

The Performance Test of Three Different Horizontal Axis Wind Turbine (HAWT) Blade Shapes Using Experimental and Numerical Methods

Stall/Post-Stall Modeling of the Longitudinal Characteristics of a General Aviation Aircraft

Blade Element Momentum Modeling of Low-Re Small UAS Electric Propulsion Systems

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