Evaluation of turbulence models for unsteady flows of an oscillating airfoil

Srinivasan, G. R.; Ekaterinaris, John A.; Mccroskey, W. J.

doi:10.1016/0045-7930(95)00016-6

Cited by 86 publications

(42 citation statements)

References 11 publications

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“…They studied on NACA 0015 airfoil by using five different turbulence model. They saw that Spalart Allmaras turbulence model had good agreement with experimental results for lift, drag and moment coefficient [9].…”

Section: Introductionmentioning

confidence: 60%

Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil

Şahi̇n¹,

Acır²

2015

IJMMM

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Abstract-In the present work, we studied numerical and experimentally analysis lift and drag performances of NACA 0015 airfoil at different attack angle at low Reynolds numbers (Re) by measuring the forces every two degrees from 0° to 20°. The experiment test was conducted in low speed wind tunnel, and the numerical analysis was performed using CFD program which was FLUENT. The results obtained from experiment and numerical were compared. In this study, stall angle depended on turbulent occurred behind airfoil was determined. As result, effect of the stall angle of airfoil performance was investigated.Index Terms-Angle of attack, CFD, NACA 0015, wind tunnel.

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Section: Introductionmentioning

confidence: 60%

Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil

Şahi̇n¹,

Acır²

2015

IJMMM

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“…2.28). With the assumption of isotropic eddy viscosity, the Reynolds stresses can be represented by: and attached flows (as seen, for instance in [70]). However, in practice it is a reasonable first approach even when these conditions are not strictly achieved.…”

Section: Turbulence Modelingmentioning

confidence: 99%

Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

Lakshminarayan

Baeder

2010

Journal of Aircraft

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In this work, a compressible Reynolds-Averaged Navier Stokes (RANS) solver is extended to investigate the aerodynamics of a micro-scale coaxial rotor configuration in hover. This required the following modifications to the solver: implementation of a time-accurate low Mach preconditioner, implementation of a sliding mesh interface boundary condition, improvements in the grid connectivity and parallelization of the code.First, an extensive validation study on the prediction capability of the solver is performed on a hovering micro-scale single rotor, for which performance data and wake characteristics have been measured experimentally. The thrust and power are reasonably well predicted for different leading and trailing geometries.Blunt leading edge geometries show poorer performance compared to the sharp leading edge geometries; the simulations show that this is mainly because of the large pressure drag acting at the blunt front. The tip vortex trajectory and velocity profiles are also well captured. The predicted swirl velocities in the wake for the micro-rotor are found to be significantly larger as compared to those for a full-scale rotor, which could be one of the reasons for additional power loss in the smaller scale rotors. The use of twist and taper is studied computationally and is seen to improve the performance of micro-rotor blades.Next, the solver is applied to simulate the aerodynamics of a full-scale coaxial rotor configuration in hover, for which performance data is available from experiments. The global quantities such as thrust and power are predicted reasonably well. In the torque trimmed situation, the top rotor shares significant percentage of the total thrust at lower thrust levels, which decreases to about 55% of the total thrust at higher thrust values. The simulations reveal that the interaction between the rotor systems is seen to generate significant impulses in the instantaneous thrust and power. The characteristic signature of this impulse is explained in terms of the blade thickness effect and loading effect, as well as blade-vortex interactions for the bottom rotor (wake effect).Finally, the RANS solver is applied to investigate the aerodynamics of a micro-scale coaxial rotor configuration in hover. The overall performance is well predicted. The interaction between the rotor systems is again seen to generate 3-8% fluctuation in the instantaneous thrust and power. The wake effect in the simulation is seen to be very prominent and the phasing of the impingement of the tip vortex from the top rotor upon the bottom rotor plays a significant role in the amount of unsteadiness on the bottom rotor. Interaction of the top rotor vortex and inboard sheet with the bottom rotor results in significant shedding on the bottom rotor blade, and this is believed to be caused by the of sharp leading edge geometry. Significant blade-vortex and vortex-vortex interactions are observed for coaxial systems.

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“…In particular, the authors used a velocity-vorticity formulation of the Navier -Stokes equations containing a vorticity transport equation, which is solved in the viscous flow zone, and an integral equation for the velocity. Ekaterinaris et al (1995) and Srinivasan et al (1995) published an extensive survey of CFD results on oscillating NACA 0012 and 0015 airfoils when using different types of turbulence models. A quasi-steady approach to unsteady flows based on this methodology has been developed by Cebeci and Jang (1990).…”

Section: Literature Surveymentioning

confidence: 99%

Analysis of horizontal axis wind turbine blade using CFD

Nigam¹,

Tenguria²,

Pradhan³

2017

Int. J. Eng. Sci. Tech

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Blade is very essential part of HAWT (horizontal axis wind turbine). Forces for Lift and drag on the blade has an important role in the wind turbine performance. The main purpose of this work is to perform CFD analysis of a blade and airfoil of wind turbine using k- SST model. In this present study NACA 63 4 -221 airfoil profile is taken for the modeling and then analysis of the blade. The lift and drag forces are calculated for the blade at different AOA (angle of attack). For present work the blade length is taken 38.98 meter, which is a redesigned blade for VESTAS V82-1.65MW horizontal axis wind turbine blade. Results obtained from simulation are compared with the experimental work found in literature.

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Evaluation of turbulence models for unsteady flows of an oscillating airfoil

Cited by 86 publications

References 11 publications

Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil

Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil

Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

Analysis of horizontal axis wind turbine blade using CFD

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