Effect of Airfoil Thickness on Flow Over the Symmetric Airfoils: Part I-Experimental Analysis (original) (raw)
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EFFECT OF AIRFOIL THICKNESS ON FLOW OVER THE SYMMETRIC AIRFOILS: PART IINUMERICAL ANALYSIS
International World Energy Conference-III, 2023
This study investigated numerically and experimentally NACA 0012, NACA 0015, and NACA 0018 airfoils at AoA=8° and Reynolds number of 1.5x105. Oil-flow visualization experiments were used to compare laminar separation bubble, separation, and reattachment results on the airfoil's upper surface with skin friction coefficient contours obtained from numerical analyses. The k-w SST transition model was run in the numerical analyses, where two different boundary conditions were tested: symmetry and wall conditions. Comparisons indicated that the transition model provided accurate results and the wall condition was in good agreement with the experimental data. The examination of aerodynamic force coefficients for symmetrical airfoils revealed that the CL value for NACA0012 was 0.6, which increased to 0.64 for the thicker NACA0015 airfoil. However, the lift force coefficient of the NACA0018 airfoil decreased to 0.52 with a further increase in thickness. Furthermore, it was observed that the drag force coefficients increased as the thickness increased.
Open Engineering, 2024
Using computational models and low-speed wind tunnel tests, the aerodynamic characteristics of the NACA 0012 airfoil with low Re numbers of (8 × 10 4 , 2 × 10 5 , 3 × 10 5 , and 4 × 10 5) and angle of attack (AOA) ranging from 0°t o 18°by two steps are examined. Using the same 3-D wind tunnel dimensions, numerical simulations were run. The software program ANSYS FLUENT was used to solve the mathematical model using the continuity equation, the Navier-Stokes equations, and the k-ω shearstress transport turbulence model. Findings demonstrate that at all AOAs, there is a direct relationship between Reynolds numbers (Re), lift and drag coefficients, kinetic energy, and stall angle. The lift coefficient rises linearly as the AOA increases, peaking at 14°, the stall angle at higher Reynolds number. The lift coefficient was found to decline when the AOA was increased further, reaching its minimal value at an AOA of 18°. With a greater AOA, the airfoil's drag coefficient rises, creating turbulent flow. The eddies produced by the turbulence cause the flow to start separating from the airfoil surface as turbulence increases. As a result, the airfoil lift coefficient drops, and its drag coefficient rises at the same time, leading to poor performance. The validation of the numerical results through wind tunnel experiments provided confidence in the findings of the study.
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2020
In the present study, the effect of hinge position (H) has been numerically investigated to find the appropriate position for improving the aerodynamic performance of the NACA 0012 flapped airfoil. In addition, perpendicular and tangential suctions have been applied to control the flow separation and enhance the aerodynamic performance over the NACA 0012 flapped airfoil at each different hinge positions. The simulations were carried out at a Reynolds number of 5 × 10 5 (Ma = 0.021) based on two-dimensional incompressible unsteady Reynolds-averaged Navier-Stokes calculations to determine the adequate hinge position. The turbulence was modeled using the shear stress transport k-ω turbulence model. The effect of perpendicular suction (θ jet = − 90°) and tangential suction (θ jet = − 30°) was computationally studied over NACA 0012 flapped airfoil for five different hinge positions (H = 0.7c, 0.75c, 0.8c, 0.85c and 0.9c) and a flap deflection (δ f) of 15°. Based on the results, the hinge position significantly affects the aerodynamic performance of the airfoil. The lift coefficient increased clearly as the hinge position moved to the trailing edge of the airfoil. Using perpendicular suction caused to increase the lift coefficient and decrease the drag coefficient. Consequently, the maximum value of the lift-to-drag ratio (C L /C D) for perpendicular and tangential suctions was achieved about 35.8% and 25.1% higher than that of the case without suction at an angle of attack of 12° and H = 0.9c. Also, the effect of perpendicular suction was more considerable compared to the tangential suction. This caused a reduction in the size of the recirculation zone from 0.5 to 0.09 of the airfoil chord length and also transferred it from 1.13 to 1.18 of the airfoil chord length.
A Study of Impacts of Airfoil Geometry on the Aerodynamic Performance at Low Reynolds Number
International Journal of Mechanical Engineering and Robotics Research
The aerodynamic performance of airfoils has been studied in several studies; however, the performance is highly relying on the airfoil geometry and the flow characteristics such as the flow type (laminar or turbulent) and Reynolds number. This paper focuses on understanding the aerodynamic performance of airfoils in a low-speed environment (low Reynolds number) versus the airfoil geometry. This paper would be a guide to the airfoil design and optimization processes toward the design target under similar flow conditions. Therefore, several parameters of the airfoil geometry, such as maximum thickness, maximum camber, their location, and reflex angle were studied in a low Reynolds number range from 0.3×10 6 to 0.8×10 6. Three airfoil parameterizations, NACA 4-digit, PARSEC, and Bezier curve, were utilised to generate the airfoil coordinates for different studied parameters. A twodimensional aerodynamic solver, XFOIL, was used to evaluate the aerodynamic performance of the airfoils. The results show that varying the airfoil geometry results in a noticeable change in the lift, drag, and moment coefficients. Also, as expected, increasing the Reynolds number has resulted in a good performance.
Effect of Reynolds Number on the Aerodynamic Performance of NACA0012 Aerofoil
IOP Conference Series: Materials Science and Engineering, 2018
The present work investigates the effect of Reynolds number on NACA0012 aerofoils for various angles of attack on the aerodynamic characteristics both experimentally as well as numerically. The modifications in the flow, as well as aerodynamic characteristics of the NACA0012 aerofoil, are systematically compared using pressure coefficient, lift coefficient, vortex shedding, etc. The study was conducted for a chord wise Reynolds number of (a) 2.21 x 10 5 and (b) 2.81 x 10 5 at an angle of attack of 0 o , 5 o , 10 o , 15 o and 20 o. A large difference in the pressure coefficient is observed between the top and bottom surface in the case of lower Reynolds number and thus it indicates that at low Reynolds number high lift is generated than at high Reynolds number. L/D study also reveals that with increasing Reynolds number the NACA0012 aerofoil losses its lifting aerodynamics property. From the vortex plot, it is clear that leading edge shedding has a negative impact on the lift of the aerofoil for 2D simulation. Thus, this paper sufficiently demonstrates the effect of Reynolds number on the aerodynamic characteristics of the NACA0012 aerofoil.
The effects of reynolds number on flow separation of Naca Aerofoil
2018
The purpose of this study is to investigate the flow separation above UTM 2D Airfoil at three different Reynolds numbers which are 1 × 106, 1.5 × 106 and 2 × 106 using pressure distribution method and flow visualization. The experiment was conducted in UTM-LST (Low Speed Tunnel). The pressure distribution is done on three different wing span, which are 40%, 50% and 70%m of span and was measured and plotted to observe the flow characteristic at angle of attack from 0° to 35° for all three different Reynolds numbers. The flow visualization method was done at 10m/s, 20m/s and 30m/s airspeed from 0° to 18°. It is concluded that the Reynolds number of 1 × 106 separates at 16° Reynolds number of 1.5 × 106 separates at 18° and Reynolds number of 2 × 106 separates at 20°.
A COMPARATIVE FLOW ANALYSIS OF NACA 6409 AND NACA 4412 AEROFOIL
In this work, flow analysis of two aerofoils (NACA 6409 and NACA 4412) was investigated. Drag force, lift force as well as the overall pressure distribution over the aerofoils were also analysed. By changing the angle of attack, variation in different properties has been observed. The outcome of this investigation was shown and computed by using ANSYS workbench 14.5. The pressure distributions as well as coefficient of lift to coefficient of drag ratio of these two aerofoils were visualized and compared. From this result, we compared the better aerofoil between these two aerofoils. The whole analysis is solely based on the principle of finite element method and computational fluid dynamics (CFD). Finally, by comparing different properties i.e drag and lift coefficients, pressure distribution over the aerofoils, it was found that NACA 4412 aerofoil is more efficient for practical applications than NACA 6409 aerofoil.
The aerodynamic performance of the NACA-4415 aerofoil section at low Reynolds numbers
1988
In this experimental investigation, the performance and the boundary layer characteristics of the NACA-4415 aerofoil section were examined for an incidence range of-5.10o~a~22.90o and for the Reynolds number range of 50,OOO~Re~600,OOO. Chordwise static pressure distributions were obtained, from which aerodynamic force and moment coefficients, namely CN, CT, and CMc/4, were calculated using a simple Trapezoidal Rule method. These pressure distributions proved to be useful for the identification and location of the various boundary layer phenomena which occurred around the aerofoil. The "surface oil" flow visualisation technique was also used and photographs were obtained to record the various flow states over the upper surface of the aerofoil. The nominal two-dimensional data obtained in this study were compared with those from other facilities and previously tested aerofoils at the University of Glasgow. These latter comparisons were for the GU25-5(11)8, GA(W)-l and NACA-0015 aerofoil sections.
A Computational Case Study on Aerodynamic parameters of NACA symmetrical Aerofoils
2021
The objective of this research is to determine the velocity and pressure field of NACA-0022 airfoil by solving the governing equation using Ansys fluent and to validate the result data of 10degree angle of attack of an airfoil with the experimental data provided by NASA such as1)Pressure coefficient. 2)Lift and drag coefficient.Also to determine the stalling angle by changing the angle of attack to 4,6,10,15,19 degree. During the research we found that The NACA 4 digit airfoil have a higher efficiency at Tip speed ratios of 7. The study of flow over NACA 4 digit airfoil is done for the Reynolds number (Re) of 105 and Richardson number (Ri) ranging from -0.5 to +0.7 at zero degree angle of attack. It has been found that with the increase in Ri, the Cl decreases almost linearly. On the contrary with the increase in Ri, the Cd increases. We found that the surface heating results in the early flow separation and is attributed to such behavior for Cl and Cd. Early flow separation leads t...
Maǧallaẗ al-baṣraẗ li-l-ʻulūm al-handasiyyaẗ, 2023
This study investigated the performance of symmetric airfoils of type NACA0012 numerically under different operating conditions. It has been assumed that the study involves steady state, non-compressive, and turbulent flows. The operating fluid was air. The effect of Reynolds number and angle of attack on lift and drag coefficients, pressure distribution, and velocity distribution was investigated. ANSYS FLUENT has been used to solve the numerical model by using continuity equations, Navier-Stokes equations, and the appropriate K-ω SST perturbation model. This study shows a clear difference between the pressure coefficient of the lower and upper surfaces of the airfoil at high Reynolds numbers, indicating higher lift at high Reynolds numbers. As the maximum stall angle of the airfoil NACA0012 is 14° after which it decreases significantly, a direct relationship was observed between lift and drag coefficients and angle of attack.