Is the Problem with the Mesh, the Turbulence Model, or the Solver? Statistical Analysis of High Lift and Drag Prediction Workshop Data

2019 ◽  
Author(s):  
Carl F. Ollivier Gooch
Keyword(s):  
Statistical Analysis ◽  
Turbulence Model ◽  
High Lift ◽  
Drag Prediction ◽  
Lift And Drag

scholarly journals A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 828
Author(s):  
Igor Rodriguez-Eguia ◽  
Iñigo Errasti ◽  
Unai Fernandez-Gamiz ◽  
Jesús María Blanco ◽  
Ekaitz Zulueta ◽  
...  
Keyword(s):  
Aerodynamic Coefficients ◽  
Trailing Edge ◽  
High Lift ◽  
Trailing Edge Flaps ◽  
Artificial Neural Network Ann ◽  
Lift And Drag ◽  
Artificial Neuronal Network ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-618, and S810, are studied in relation to three combinations of the following parameters: angle of attack, flap angle (deflection), and flaplength. Results are in concordance with the aerodynamic results expected when studying a TEF on an airfoil, showing the effect exerted by the three parameters on both aerodynamic coefficients lift and drag. Depending on whether the airfoil flap is deployed on either the pressure zone or the suction zone, the lift-to-drag ratio, CL/CD, will increase or decrease, respectively. Besides, the use of a larger flap length will increase the higher values and decrease the lower values of the CL/CD ratio. In addition, an artificial neural network (ANN) based prediction model for aerodynamic forces was built through the results obtained from the research.

Study of High-Lift Configurations Using k-? Transition/Turbulence Model

2000 ◽  
Vol 37 (6) ◽  
pp. 1008-1016 ◽  
Author(s):  
Ryan Czerwiec ◽  
J. R. Edwards ◽  
C. L. Rumsey ◽  
A. Bertelrud ◽  
H. A. Hassan
Keyword(s):  
Turbulence Model ◽  
High Lift

scholarly journals CFD Investigation of Fluid Flow Over Aerofoil With and Without Dimple

2020 ◽  
Author(s):  
Uzair Sajjad ◽  
Khalid Hamid ◽  
Naseem Abbas
Keyword(s):  
Boundary Layer ◽  
Fluid Flow ◽  
Cross Section ◽  
Turbulence Model ◽  
Aerodynamic Performance ◽  
3D Analysis ◽  
Cad Model ◽  
Uniform Cross Section ◽  
Solid Works ◽  
Lift And Drag

Abstract This work labels the effect of dimples on aerodynamic performance of an airfoil. NACA 0018 having a uniform cross section has been evaluated in this study. Eclipse dimpled airfoil is tested and compared with plain airfoil and with the airfoil in the literature [23,24]. Flows taken into consideration are subsonic. The CAD model is drawn in Solid works 2016, while the simulations are performed in Ansys 18.3. A 2-D CFD investigation is performed on both models using k-w turbulence model, subsequently the better one is selected based on the results. 3D analysis is performed on a segment of airfoil having one dimple. Lift and drag coefficients are calculated for various angles of attack. This investigation tells that dimples affect the aerodynamics of airfoil, particularly for various angle of attacks. For smaller angle of attacks, plain airfoil showed less drag and higher lift, but totally different trend is achieved with increasing angle of attack whereas 20° was found to be the optimum angle. The findings proved that dimples on the surface delay the separation of boundary layer by generating additional turbulence on the surface and consequently reduce the formation of wake, which in turn decreases drag significantly.

Lift and Drag Characteristics of an Airfoil and Feedback Flow Control by Flap Actuators in the Low Reynolds Number Region

2015 ◽  
Author(s):  
Toshiki Mori ◽  
Masashi Yamaguchi ◽  
Kyoji Inaoka ◽  
Mamoru Senda
Keyword(s):  
Reynolds Number ◽  
Wind Speed ◽  
Unsteady Flow ◽  
Flow Control ◽  
Flow Condition ◽  
Low Reynolds Number ◽  
High Lift ◽  
Unsteady Flow Condition ◽  
Lift And Drag ◽  
Drag Ratio

The present paper describes the applicability of the flow control device, mini actuators attached on the leading edge of an airfoil, for the flow separation control under unsteady flow condition in the low Reynolds number region. Lift and drag have been measured for a wide variety of the wind speeds (Reynolds numbers) and the angles of attack. Then, effects of simple feedback flow control, where the time-dependent signal of the lift-drag ratio has been used as an input to detect the stall and served as a trigger to start the actuation, have been explored under the unsteady flow condition for evading the stall. For every Reynolds number from 30,000 to 80,000, the actuators worked quite well to delay the stall, increasing both in the lift and the stall angle of attack. Then, threshold value of the lift-drag ratio was determined to detect the stall. Effectiveness of the feedback control of the actuation was demonstrated under the condition of the wind speed decrease which would lead to the stall if no-actuation. Immediately after the velocity decrease, the decrease in the lift-drag ratio below the threshold were detected and the dynamic actuations were started, resulting in evading the stall and keeping high lift. The additional operation of the feedback, stopping the actuation when the lift-drag ratio showed lower than the second threshold, was revealed effective to keep the high lift force under the condition combined with the wind speed increase and decrease.

scholarly journals Statistical Analysis of the Sixth AIAA Drag Prediction Workshop Solutions

2018 ◽  
Vol 55 (4) ◽  
pp. 1388-1400 ◽  
Author(s):  
Joseph M. Derlaga ◽  
Joseph H. Morrison
Keyword(s):  
Statistical Analysis ◽  
Drag Prediction
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