Simulating Drag and Lift Coefficient Variation of the MI VAWT1 airfoil with Angle of Attack at Low Reynolds Number

A solar-powered unmanned aerial vehicle generally encounters the problems that it has low Reynolds effects and is highly susceptible to gust response. Therefore, the grid velocity method was used to analyze the gust response characteristics of the airfoil FX63-137 under low Reynolds number. First, the reliability of the numerical simulation method at low Reynolds number and grid velocity method were verified with experimental data. Second, the gust response characteristics of FX63-137 airfoil under different Reynolds numbers and different angles of attack were numerically simulated. The results show that the magnitude of incremental lift coefficient in gust response decreases because laminar separation bubbles are complete as the Reynolds number decreases at a small angle of attack. They also show that laminar separation bubbles have an unloaded effect on gust response. At a high angle of attack, as the airfoil enters into stalling stage, the incremental lift coefficient begins to decline before reaching maximum gust disturbance. Because of the stalling of the airfoil, when the gust disappears, the incremental lift coefficient has a negative value. What's more, although the effective angle of attack is equal, the flow structure of the airfoil is somewhat different in upstream and downstream moments. Compared with the downstream moment, the incremental lift coefficient at the upstream moment is generally larger, and the incremental lift coefficient curve of the airfoil forms a non-closed hysteresis loop.

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Evolution of the Non-linear and Unsteady Low Reynolds Number Laminar Separation Bubble around the Airfoil with Small angle of attack

46th AIAA Fluid Dynamics Conference ◽

10.2514/6.2016-4337 ◽

2016 ◽

Author(s):

Bai Peng ◽

Feng Li ◽

Qiang Liu ◽

Huiling Zhan

Keyword(s):

Reynolds Number ◽

Small Angle ◽

Separation Bubble ◽

Low Reynolds Number ◽

Angle Of Attack ◽

Laminar Separation Bubble ◽

Laminar Separation ◽

Non Linear ◽

Low Reynolds

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Aerodynamic and Vibration Characteristics of the Micro-Octocopter at Low Reynolds Number

Mobile Information Systems ◽

10.1155/2021/3691559 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Xiaohua Zou ◽

Mingsheng Ling ◽

Wenzheng Zhai

Keyword(s):

Reynolds Number ◽

Load Capacity ◽

Lift Coefficient ◽

Angle Of Attack ◽

Aerodynamic Characteristics ◽

Vibration Characteristics ◽

Low Reynolds ◽

Vibration Performance ◽

Drag Ratio ◽

Lift To Drag Ratio

With the development of flight technology, the need for stable aerodynamic and vibration performance of the aircraft in the civil and military fields has gradually increased. In this case, the requirements for aerodynamic and vibration characteristics of the aircraft have also been strengthened. The existing four-rotor aircraft carries limited airborne equipment and payload, while the current eight-rotor aircraft adopts a plane layout. The size of the propeller is generally fixed, including the load capacity. The upper and lower tower layout analyzed in this paper can effectively solve the problems of insufficient four-axis load and unstable aerodynamic and vibration performance of the existing eight-axis aircraft. This paper takes the miniature octorotor as the research object and studies the aerodynamic characteristics of the miniature octorotor at different low Reynolds numbers, different air pressures and thicknesses, and the lift coefficient and lift-to-drag ratio, as well as the vibration under different elastic moduli and air pressure characteristics. The research algorithm adopted in this paper is the numerical method of fluid-solid cohesion and the control equation of flow field analysis. The research results show that, with the increase in the Reynolds number within a certain range, the aerodynamic characteristics of the miniature octorotor gradually become better. When the elastic modulus is 2.5 E, the aircraft’s specific performance is that the lift increases, the critical angle of attack increases, the drag decreases, the lift-to-drag ratio increases significantly, and the angle of attack decreases. However, the transition position of the flow around the airfoil surface is getting closer to the leading edge, and its state is more likely to transition from laminar flow to turbulent flow. When the unidirectional carbon fiber-reinforced thickness is 0.2 mm and the thin arc-shaped airfoil with the convex structure has a uniform thickness of 2.5% and a uniform curvature of 4.5%, the aerodynamic and vibration characteristics of the octorotor aircraft are most beneficial to flight.

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Experimental Investigation of Drag and Lift Forces on Microparticles in Low Reynolds Number Poiseuille Flow in Microchannel

Journal of Dispersion Science and Technology ◽

10.1080/01932691.2016.1138868 ◽

2016 ◽

Vol 37 (12) ◽

pp. 1767-1777 ◽

Cited By ~ 2

Author(s):

Reza Razaghi ◽

Mohammad Hassan Saidi

Keyword(s):

Experimental Investigation ◽

Reynolds Number ◽

Poiseuille Flow ◽

Low Reynolds Number ◽

Lift Forces ◽

Low Reynolds ◽

Drag And Lift

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Determine Aerodynamic Characteristics for FX63-137 Aerofoil by Using Subsonic Wind Tunnel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.695.651 ◽

2014 ◽

Vol 695 ◽

pp. 651-654 ◽

Cited By ~ 1

Author(s):

Magedi Moh M. Saad ◽

Norzelawati Asmuin

Keyword(s):

Reynolds Number ◽

Aluminum Alloy ◽

Wind Tunnel ◽

Low Reynolds Number ◽

Angle Of Attack ◽

Aerodynamic Characteristics ◽

Cnc Machine ◽

Subsonic Wind Tunnel ◽

Low Reynolds

This paper is primarily concentrated with determining aerodynamic characteristics and choosing the best angle of attack at a maximum lift and low drag for the FX 63-137 aerofoil at a low Reynolds number and a speed of 20m/s and 30m/s, by using subsonic wind tunnel through manufacturing the aerofoil by aluminum alloy using a CNC machine. The proposed methodology is divided into several stages. Firstly, manufacturing the aerofoil using an aluminum alloy. Secondly, the testing process is carried out using subsonic wind tunnel. Thirdly, the results are displayed and compared with results produced from related works, in order to find out the best angle of attack at a maximum lift.

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Flow around a hemisphere-cylinder at high angle of attack and low Reynolds number. Part II: POD and DMD applied to reduced domains

Aerospace Science and Technology ◽

10.1016/j.ast.2014.10.009 ◽

2015 ◽

Vol 44 ◽

pp. 88-100 ◽

Cited By ~ 29

Author(s):

Soledad Le Clainche ◽

Daniel Rodríguez ◽

Vassilis Theofilis ◽

Julio Soria

Keyword(s):

Reynolds Number ◽

Low Reynolds Number ◽

Angle Of Attack ◽

High Angle ◽

High Angle Of Attack ◽

Low Reynolds

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Numerical Study of Winglet Cant Angle Effect on Wing Performance at Low Reynolds Number

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.393.366 ◽

2013 ◽

Vol 393 ◽

pp. 366-371

Author(s):

C.F. Mat Taib ◽

Abdul Aziz Jaafar ◽

Salmiah Kasolang

Keyword(s):

Reynolds Number ◽

Numerical Analysis ◽

Numerical Study ◽

Low Reynolds Number ◽

Lift Coefficient ◽

Wing Model ◽

Low Reynolds ◽

Wing Performance ◽

Drag Ratio ◽

Lift To Drag Ratio

The study on the effect of winglet shape in wing design has been a focus of many researchers. Nevertheless, the effect of cant angle on the wing performances at low Reynolds number has not been fully explored. This paper describes the effect of a single semi-circular shaped winglet attached with a rectangular wing model to lower the drag without increasing the span of the wing. Aerodynamic characteristics for the rectangular wing (NACA 65-3-218) with and without semi-circular winglets have been studied using STAR CCM+ 4.0. This numerical analysis is based on Finite Volume Approach. Simulations were carried out on the rectangular wing model with and without winglet at aspect ratio of 2.73 and Reynolds number of 0.16 x 10 6 for various angles of attack. From the numerical analysis, wing performance characteristics in terms of lift coefficient CL, drag coefficient CD, and lift-to-drag ratio, CL/CD were obtained. It was found that the addition of a semi-circular winglet has resulted in a larger lift curve slope and higher Lift-to-Drag ratio in comparison with the case of a wing without winglet. Further investigation has revealed that a wing with semi-circular winglet with cant angle of 45 degree has produced the best Lift-to-Drag ratio, CL/CD.

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Aerodynamic Performance of Micro Aerial Wing Structures at Low Reynolds Number

INCAS BULLETIN ◽

10.13111/2066-8201.2019.11.1.8 ◽

2019 ◽

Vol 11 (1) ◽

pp. 107-120 ◽

Cited By ~ 1

Author(s):

Y. D. DWIVEDI ◽

Vasishta BHARGAVA ◽

P. M. V. RAO ◽

Donepudi JAGADEESH

Keyword(s):

Reynolds Number ◽

Low Reynolds Number ◽

Lift Coefficient ◽

Reynolds Numbers ◽

Aerodynamic Performance ◽

Panel Method ◽

Experiment Data ◽

Wing Structures ◽

Low Reynolds ◽

Good Agreement

Corrugations are folds on a surface as found on wings of dragon fly insects. Although they fly at relatively lower altitudes its wings are adapted for better aerodynamic and aero-elastic characteristics. In the present work, three airfoil geometries were studied using the 2-D panel method to evaluate the aerodynamic performance for low Reynolds number. The experiments were conducted in wind tunnel for incompressible flow regime to demonstrate the coefficients of lift drag and glide ratio at two Reynolds numbers 1.9x104 and 1.5x105 and for angles of attack ranging between 00 and 160. The panel method results have been validated using the current and existing experiment data as well as with the computational work from cited literature. A good agreement between the experimental and the panel methods were found for low angles of attack. The results showed that till 80 angle of attack higher lift coefficient and lower drag coefficient are obtainable for corrugated airfoils as compared to NACA 0010. The validation of surface pressure coefficients for all three airfoils using the panel method at 40 angles of attack was done. The contours of the non-dimensional pressure and velocity are illustrated from -100 to 200 angles of attack. A good correlation between the experiment data and the computational methods revealed that the corrugated airfoils exhibit better aerodynamic performance than NACA 0010.

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