scholarly journals Box Wing: Aerodynamic experimental study for applications in MAVs

2020 ◽  
Author(s):  
Mohit SIngh ◽  
Jasmine Jerry Aloor ◽  
Annanya Singh ◽  
Sandeep Saha
Keyword(s):  
Wind Tunnel ◽  
Cfd Simulation ◽  
Lift Coefficient ◽  
Flow Visualisation ◽  
Scaled Model ◽  
Wing Model ◽  
Induced Drag ◽  
Aerial Vehicles ◽  
Stall Angle ◽  
Joined Wing

Advancements in the field of aerial robotics and micro aerial vehicles (MAVs) have increased the demand for high payload capabilities. Closed wing designs like the annular wing, the joined wing, the box wing and spiroid tip devices improve the aerodynamic performance by suppressing the wingtip vortices along with an enhanced lift coefficient. A box wing may be defined as a wing that effectively has two main planes which merge at their ends so that there are no conventional wingtips. We propose the implementation of box wings as the main lifting surface for such systems. Box wings have a potential of generating lift with considerably less induced drag and delayed stall angles than monoplane wings. We study the aerodynamic aspects of a box wing model using wind tunnel tests and numerical simulations. We conducted Computational Fluid Dynamics (CFD) simulation subjecting the model to a steady flow and later analysed the vortex core using CFD tools. Wind tunnel measurements of the forces were obtained using sting balance. Furthermore, polyester thread tufts and smoke flow visualisation were performed to understand the qualitative behaviour of the scaled model in the open to atmosphere, suction type tunnel. Our results reveal an increase in the lift to drag (L/D) ratio of the wing by 25 % and a delay in the model’s stall angle by +6° compared to a monoplane; implying a lower stalling speed for mini unmanned aerial vehicles (UAVs) and MAVs. These advancements if applied could revolutionize the capabilities of intelligent flying systems by enabling them to carry better sensors, computational units and other payloads as per the mission.

scholarly journals EXPERIMENTAL ANALYSIS OF DOUBLE BOX WING UAV.

2022 ◽  
pp. 14-19
Author(s):  
Sai Adithya Vanga ◽  
Moulshree Srivastava ◽  
Y. D. Dwivedi
Keyword(s):  
Wind Tunnel ◽  
Unmanned Aerial Vehicles ◽  
Preliminary Analysis ◽  
Computational Analysis ◽  
Computational Results ◽  
Wing Model ◽  
Induced Drag ◽  
Aerial Vehicles ◽  
Payload Capacity ◽  
Fuel Consumption And Emissions

In an attempt to reduce the induced drag on a wing, Prandtl found that induced drag reduced significantly by highly increasing the number of vertically offset wings. The same result could be obtained by joining the wingtips of two vertically offset wings. This helped increase payload capacity and also reduced fuel consumption and emissions. Such a wing configuration came to be known as Prandtl’s box wing. In this work, the design and analysis of a box wing aircraft model has been carried out. The preliminary analysis is performed using XFLR5, and the computational analysis is done with the help of ANSYS 18.2. The values of experiments are computed with the help of MATLab R2017. The box wing model has shown a nearly 53.74% reduction in drag as compared with conventional wing models. The computational results of drag have been compared and validated with the results of analytical and the experimental results from the wind tunnel and found to be within 10% of the computational result. Since the drag of the box wing is significantly lesser than the conventional wings the box wing is a feasible configuration which can be used to design various aircrafts including Unmanned Aerial Vehicles and Commercial Planes.

scholarly journals Design and Validation of a New Morphing Camber System by Testing in the Price—Païdoussis Subsonic Wind Tunnel

Aerospace ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 23 ◽  
Author(s):  
David Communier ◽  
Ruxandra Mihaela Botez ◽  
Tony Wong
Keyword(s):  
Wind Tunnel ◽  
Unmanned Aerial Vehicle ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Trailing Edge ◽  
Subsonic Wind Tunnel ◽  
Aerial Vehicle ◽  
Stall Angle

This paper presents the design and wind tunnel testing of a morphing camber system and an estimation of performances on an unmanned aerial vehicle. The morphing camber system is a combination of two subsystems: the morphing trailing edge and the morphing leading edge. Results of the present study show that the aerodynamics effects of the two subsystems are combined, without interfering with each other on the wing. The morphing camber system acts only on the lift coefficient at a 0° angle of attack when morphing the trailing edge, and only on the stall angle when morphing the leading edge. The behavior of the aerodynamics performances from the MTE and the MLE should allow individual control of the morphing camber trailing and leading edges. The estimation of the performances of the morphing camber on an unmanned aerial vehicle indicates that the morphing of the camber allows a drag reduction. This result is due to the smaller angle of attack needed for an unmanned aerial vehicle equipped with the morphing camber system than an unmanned aerial vehicle equipped with classical aileron. In the case study, the morphing camber system was found to allow a reduction of the drag when the lift coefficient was higher than 0.48.

Wind Tunnel Experimental Study of Wind Turbine Airfoil Aerodynamic Characteristics

2012 ◽  
Vol 260-261 ◽  
pp. 125-129
Author(s):  
Xin Zi Tang ◽  
Xu Zhang ◽  
Rui Tao Peng ◽  
Xiong Wei Liu
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Aerodynamic Characteristics ◽  
Wind Turbine Blades ◽  
High Lift ◽  
Minimum Drag ◽  
Stall Angle ◽  
High Reynolds

High lift and low drag are desirable for wind turbine blade airfoils. The performance of a high lift airfoil at high Reynolds number (Re) for large wind turbine blades is different from that at low Re number for small wind turbine blades. This paper investigates the performance of a high lift airfoil DU93-W-210 at high Re number in low Re number flows through wind tunnel testing. A series of low speed wind tunnel tests were conducted in a subsonic low turbulence closed return wind tunnel at the Re number from 2×105to 5×105. The results show that the maximum lift, minimum drag and stall angle differ at different Re numbers. Prior to the onset of stall, the lift coefficient increases linearly and the slope of the lift coefficient curve is larger at a higher Re number, the drag coefficient goes up gradually as angle of attack increases for these low Re numbers, meanwhile the stall angle moves from 14° to 12° while the Re number changes from 2×105to 5×105.

scholarly journals Experimental and Computational Investigation of Spoiler Deployment on Wing Stall

2021 ◽  
Author(s):  
Scott Lindsay
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Computational Study ◽  
Lift Coefficient ◽  
Wind Tunnel Experiment ◽  
Chord Length ◽  
Aerodynamic Efficiency ◽  
Stall Angle ◽  
Wing Stall ◽  
High Angles Of Attack

Upper surface flaps commonly referred to as spoilers or drag brakes can increase maximum lift, and improve aerodynamic efficiency at high, near-stall angles of attack. This phenomenon was studied experimentally and computationally using a 0.307626 m chord length NACA 2412 airfoil in six different configurations, and one baseline clean configuration. A wind tunnel model was placed in the Ryerson Low Speed Wind Tunnel (atmospheric, closed-circuit, 3 ft × 3 ft test section) at a Reynold’s number of approximately 780,000 and a Mach number of 0.136. The wind tunnel study increased the lift coefficient by 0.393%-2.497% depending on the spoiler configuration. A spoiler of 10% chord length increased the maximum lift coefficient by 2.497 % when deflected 8º, by 2.110% when deflected 15º, and reduced the maximum lift coefficient by 2.783% when deflected 25º. A spoiler of 15% chord length produced smaller maximum lift coefficient gains; 0.393% when deflected 8º, by 1.760% when deflected 15º, and reduced the maximum lift coefficient by 4.475% when deflected 25º. Deflecting the spoiler increased the stall angle between 37.658% and 87.544% when compared with the clean configuration. The drag coefficient of spoiler configurations was lower than the clean configuration at angles of attack above 18º. The combination of the increased lift and reduced drag at angles of attack above 18º created by the spoiler configurations resulted in a higher aerodynamic efficiency than the clean configuration case. A 10% chord length spoiler deflected at 8º produced the highest aerodynamic efficiency gains. At low angles of attack, the computational study produced consistently higher lift coefficients compared with the wind tunnel experiment. The lift-slope was consistent with the wind tunnel experiment lift-slope. The spoiler airfoil stall behaviour was inconsistent with the results from the wind tunnel experiment. The drag coefficient results were consistent with the wind tunnel experiment at low angles of attack. However, the spoiler equipped airfoils did not reduce drag at high angles of attack. Therefore, the computational model was not valid for the spoiler configurations at high angles of attack.

scholarly journals Experimental and Computational Investigation of Spoiler Deployment on Wing Stall

2021 ◽  
Author(s):  
Scott Lindsay
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Computational Study ◽  
Lift Coefficient ◽  
Wind Tunnel Experiment ◽  
Chord Length ◽  
Aerodynamic Efficiency ◽  
Stall Angle ◽  
Wing Stall ◽  
High Angles Of Attack

Upper surface flaps commonly referred to as spoilers or drag brakes can increase maximum lift, and improve aerodynamic efficiency at high, near-stall angles of attack. This phenomenon was studied experimentally and computationally using a 0.307626 m chord length NACA 2412 airfoil in six different configurations, and one baseline clean configuration. A wind tunnel model was placed in the Ryerson Low Speed Wind Tunnel (atmospheric, closed-circuit, 3 ft × 3 ft test section) at a Reynold’s number of approximately 780,000 and a Mach number of 0.136. The wind tunnel study increased the lift coefficient by 0.393%-2.497% depending on the spoiler configuration. A spoiler of 10% chord length increased the maximum lift coefficient by 2.497 % when deflected 8º, by 2.110% when deflected 15º, and reduced the maximum lift coefficient by 2.783% when deflected 25º. A spoiler of 15% chord length produced smaller maximum lift coefficient gains; 0.393% when deflected 8º, by 1.760% when deflected 15º, and reduced the maximum lift coefficient by 4.475% when deflected 25º. Deflecting the spoiler increased the stall angle between 37.658% and 87.544% when compared with the clean configuration. The drag coefficient of spoiler configurations was lower than the clean configuration at angles of attack above 18º. The combination of the increased lift and reduced drag at angles of attack above 18º created by the spoiler configurations resulted in a higher aerodynamic efficiency than the clean configuration case. A 10% chord length spoiler deflected at 8º produced the highest aerodynamic efficiency gains. At low angles of attack, the computational study produced consistently higher lift coefficients compared with the wind tunnel experiment. The lift-slope was consistent with the wind tunnel experiment lift-slope. The spoiler airfoil stall behaviour was inconsistent with the results from the wind tunnel experiment. The drag coefficient results were consistent with the wind tunnel experiment at low angles of attack. However, the spoiler equipped airfoils did not reduce drag at high angles of attack. Therefore, the computational model was not valid for the spoiler configurations at high angles of attack.

scholarly journals Experimental and Numerical Analysis of the Effect of Vortex Generator Height on Vortex Characteristics and Airfoil Aerodynamic Performance

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 959 ◽  
Author(s):  
Xinkai Li ◽  
Ke Yang ◽  
Xiaodong Wang
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Average Kinetic Energy ◽  
Control Effect ◽  
Height Range ◽  
Stall Angle ◽  
Drag Ratio

To explore the effect of the height of vortex generators (VGs) on the control effect of boundary-layer flow, the vortex characteristics of a plate and the aerodynamic characteristics of an airfoil for VGs were studied by both wind tunnel experiments and numerical methods. Firstly, the ratio of VG height (H) to boundary layer thickness (δ) was studied on a flat plate boundary layer; the values of H are 0.1δ, 0.2δ, 0.5δ, 1.0δ, 1.5δ, and 2.0δ. Results show that the concentrated vortex intensity and VG height present a logarithmic relationship, and vortex intensity is proportional to the average kinetic energy of the fluid in the height range of the VG. Secondly, the effects of height on the aerodynamic performance of airfoils were studied in a wind tunnel using three VGs with H = 0.66δ, 1.0δ, and 1.33δ. The stall angle of the airfoil with and without VGs is 18° and 8°, respectively, so the VGs increase the stall angle by 10°. The maximum lift coefficient of the airfoil with VGs increases by 48.7% compared with the airfoil without VGs, and the drag coefficient of the airfoil with VGs is 84.9% lower than that of the airfoil without VGs at an angle of attack of 18°. The maximum lift–drag ratio of the airfoil with VGs is lower than that of the airfoil without VGs, so the VGs do not affect the maximum lift–drag ratio of the airfoil. However, a VG does increase the angle of attack of the best lift–drag ratio.

scholarly journals Design, Manufacturing, and Testing of a New Concept for a Morphing Leading Edge using a Subsonic Blow Down Wind Tunnel

Biomimetics ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 76
Author(s):  
David Communier ◽  
Franck Le Besnerais ◽  
Ruxandra Mihaela Botez ◽  
Tony Wong
Keyword(s):  
Wind Tunnel ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Test Results ◽  
Deformation Method ◽  
Blow Down ◽  
Aerial Vehicle ◽  
Compliance Mechanism ◽  
Stall Angle

This paper presents the design and wind tunnel test results of a wing including a morphing leading edge for a medium unmanned aerial vehicle with a maximum wingspan of 5 m. The design of the morphing leading edge system is part of research on the design of a morphing camber system. The concept presented here has the advantage of being simple to manufacture (wooden construction) and light for the structure of the wing (compliance mechanism). The morphing leading edge prototype demonstrates the possibility of modifying the stall angle of the wing. In addition, the modification of the stall angle is performed without affecting the slope of the lift coefficient. This prototype is designed to validate the functionality of the deformation method applied to the leading edge of the wing. The mechanism can be further optimized in terms of shape and material to obtain a greater deformation of the leading edge, and, thus, to have a higher impact on the increase of the stall angle than the first prototype of the morphing leading edge presented in this paper.

scholarly journals Investigations of Lift and Drag Performances on Neo-Ptero Micro UAV Models

2021 ◽  
Vol 84 (2) ◽  
pp. 50-62
Author(s):  
Noor Iswadi Ismail ◽  
Mahamad Hisyam Mahamad Basri ◽  
Hazim Sharudin ◽  
Zurriati Mohd Ali ◽  
Ahmad Aliff Ahmad Shariffuddin ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Successful Development ◽  
Aerodynamic Efficiency ◽  
Trade Off ◽  
Flight Stability ◽  
Stall Angle ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

This paper presents the investigation and improvement of lift and drag characteristics of Neo-Ptero micro-UAV models based on the virtual wind tunnel method. Despite its successful development and flight stability, the lift and drag coefficients characteristics of the current Mark 1 Neo-Ptero remain unknown. To improve the Mark 1 Neo-Ptero performances, Mark 2 Neo-Ptero model has given a new unsymmetrical airfoil wing configuration. The computational aerodynamic analysis was executed and focused on certain lift and drag coefficient characteristics. Lift coefficient results showed that Mark 2 improved in overall lift characteristics such as zero-lift angle, maximum lift magnitude and stall angle magnitude. Conversely, Mark 2 model suffered a slightly higher drag coefficient magnitude and more significant drag increment percentage than Mark 1. However, the trade-off between superior lift magnitude and minor drag generation induced by Mark 2 boosts the model’s aerodynamic efficiency performances but is only limited at early angle stages.

scholarly journals Studi Numerik dan Eksperimen Aerodinamika Airfoil NACA 24112

2021 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Dhedhek Wahyu Aji Perdana ◽  
Marwan Effendy
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Flow Velocity ◽  
Experimental Test ◽  
Test Specimen ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Flow Visualisation ◽  
Simulation Results

This study aims to investigate experimentally and numerically the characteristics of the NACA 24112 airfoil. This study focuses on investigations of lift coefficient (CL), drag coefficient (CD), and CL / CD ratio and pressure, including flow visualisation around the airfoil. The study was conducted at an angle of attack ranging to -15°-20° and various Mach number at  0.0728 and 0.0809. The experimental test used a test specimen with a span dimension of 20 cm and a chord of 10 cm with an open wind tunnel. A total of 376,500 square elements with values ∆y + to 9.6 were successfully generated to achieve the accuracy of the simulation. The results showed that the CL and CD values obtained from the experimental and simulation results showed a similar trend. The CD value of the experimental results is greater than the simulation results. The CL and CD values will increase with increasing flow velocity and increasing the angle of attack. A stall occurs at an attack angle of 20°.

scholarly journals Gliding Birds: The Effect of Variable Wing Span

1987 ◽  
Vol 133 (1) ◽  
pp. 33-58 ◽  
Author(s):  
VANCE A. TUCKER
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Lift Coefficient ◽  
Polar Curve ◽  
Wing Span ◽  
Induced Drag ◽  
Black Vulture ◽  
Polar Area ◽  
Air Speed ◽  
Performance Area

The equilibrium gliding performance of a bird is described by the relationship between sinking speed (V8) and air speed (V). When V9 is plotted against V, the points fall in a ‘performance area’ because the wing span is changed during gliding. The lowest V3 for each V in the performance area defines a ‘maximum performance curve’. This curve can be predicted by a mathematical model that changes the wing span, area and profile drag coefficient (CD, pr) of a hypothetical bird to minimize drag. The model can be evaluated for a particular species given (a) a linear function relating wing area to wing span, and (b) a ‘polar curve’ that relates CDpr and the lift coefficient (CL) of the wings. For rigid wings, a single polar curve relates CDpr to CL values at a given Reynolds number. The position and shape of the polar curve depend on the aerofoil section of the wing and the Reynolds number. In contrast, the adjustable wings of a laggar falcon (Falco jugger) and a black vulture (Coragyps atratus) gliding in a wind tunnel have CL, and CD,pr values that fall in a ‘polar area’ rather than on a curve. The minimum values of CD,pr at each CL bound the polar area and define a polar curve that is suitable for evaluating the model. Although the falcon and the vulture have wings that are markedly different in appearance, the data for either bird are enclosed by the same polar area, and fitted by the same polar curve for minimum CD,pr at each CL value. This curve is a composite of the polar curves for rigid wings with aerofoils similar to those found in avian wings. These observations suggest that the polar curves of other gliding birds may be similar to that of the falcon and the vulture. Other polar curves are defined by CL and CD,pr values for the falcon and the vulture gliding at a constant speed but at different glide angles. Each speed has a different polar curve; but for a given speed, the same polar curve fits the data foreither bird. The falcon and the vulture gliding in the wind tunnel at a given speed were found to increase their drag by decreasing their wing span. This change increases induced drag and probably increases CD,pr for the inner parts of the wing because of an unusual property of bird-like aerofoil sections: wings with such sections have minimum values of CDpr at CL values near 1, while conventional wings have minimum values of CD,Pr at CL values near 0.

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