scholarly journals Effect of Ground Proximity on Aerodynamic Characteristics of NACA 4412 Airfoil.

2022 ◽  
pp. 96-104
Author(s):  
Aditi Deekshita Pallay ◽  
Abdul Wahab ◽  
Akhil Shesham ◽  
Y D Dwivedi
Keyword(s):  
Wind Tunnel ◽  
Flow Behavior ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Vital Role ◽  
Ground Clearance ◽  
Induced Drag ◽  
Good Accordance ◽  
Low Speed Wind Tunnel

Ground effect plays a vital role in modulating the flow behavior over any streamlined body. The most widely used wing-in ground effect (WIG) aircrafts and seaplanes utilize this phenomenon in order to enhance the aerodynamic performance during the landing and take-off phases of flight. This paper investigates the aerodynamics of ground effect on a NACA 4412 rectangular wing without end plates. The experiment was conducted in a low-speed wind tunnel at Re=2×105 for the ground clearance of 1 and 0.5 of the chord, measured from the maximum thickness position on the airfoil. The pressure distribution over the chord length was recorded for α=3° and 6° to verify the effect of ground clearance during takeoffs. The results have shown to be in good accordance with the literature, as the coefficient of lift augmented with increase in ground proximity and the induced drag was minimized.

Aerodynamic performance improvement of WIG aircraft

2017 ◽  
Vol 89 (1) ◽  
pp. 120-132 ◽  
Author(s):  
Mojtaba Tahani ◽  
Mehran Masdari ◽  
Ali Bargestan
Keyword(s):  
Dihedral Angle ◽  
Twist Angle ◽  
Lift Coefficient ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Sweep Angle ◽  
Content Type ◽  
Ground Clearance ◽  
Geometrical Characteristics

Purpose This paper aims to investigate the aerodynamic characteristics as well as static stability of wing-in-ground effect aircraft. The effect of geometrical characteristics, namely, twist angle, dihedral angle, sweep angle and taper ratio are examined. Design/methodology/approach A three-dimensional computational fluid dynamic code is developed to investigate the aerodynamic characteristics of the effect. The turbulent model is utilized for characterization of flow over wing surface. Findings The numerical results show that the maximum change of the drag coefficient depends on the angle of attack, twist angle and ground clearance, in a decreasing order. Also, it is found that the lift coefficient increases as the ground clearance, twist angle and dihedral angle decrease. On the other hand, the sweep angle does not have a significant effect on the lift coefficient for the considered wing section and Reynolds number. Also, as the aerodynamic characteristics increase, the taper ratio befits in trailing state. Practical implications To design an aircraft, the effect of each design parameter needs to be estimated. For this purpose, the sensitivity analysis is used. In this paper, the influence of all parameter against each other including ground clearance, angle of attack, twist angle, dihedral angle and sweep angle for the NACA 6409 are investigated. Originality/value As a summary, the contribution of this paper is to predict the aerodynamic performance for the cruise condition. In this study, the sensitivity of the design parameter on aerodynamic performance can be estimated and the effect of geometrical characteristics has been investigated in detail. Also, the best lift to drag coefficient for the NACA 6409 wing section specifies and two types of taper ratios in ground effect are compared.

scholarly journals Features of flow around transport aircraft model with running propellers by modelled engine failure in wind tunnel

2021 ◽  
Vol 2103 (1) ◽  
pp. 012206
Author(s):  
V I Chernousov ◽  
A A Krutov ◽  
E A Pigusov
Keyword(s):  
Wind Tunnel ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Light Transport ◽  
Transport Aircraft ◽  
Engine Failure ◽  
The One ◽  
Low Speed Wind Tunnel ◽  
Control Surfaces ◽  
Landing Mode

Abstract This paper presents the experiment results of modelling the one engine failure at the landing mode on a model of a light transport airplane in the T-102 TsAGI low speed wind tunnel. The effect of starboard and port engines failure on the aerodynamic characteristics and stability of the model is researched. The model maximum lift coefficient is reduced about ≈8% and there are the same moments in roll and yaw for starboard and port engines failure case. It was found that the failure of any engine has little impact on the efficiency of control surfaces. Approaches of compensation of forces and moments arising in the engine failure case were investigated.

Experimental Aerodynamic Characteristics of a Compound Wing in Ground Effect

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Saeed Jamei ◽  
Adi Maimun Abdul Malek ◽  
Shuhaimi Mansor ◽  
Nor Azwadi Che Sidik ◽  
Agoes Priyanto
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Center Of Pressure ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Ground Effect ◽  
Reynolds Numbers ◽  
Aerodynamic Characteristics ◽  
Ground Clearance

Wing configuration is a parameter that affects the performance of wing-in-ground effect (WIG) craft. In this study, the aerodynamic characteristics of a new compound wing were investigated during ground effect. The compound wing was divided into three parts with a rectangular wing in the middle and two reverse taper wings with anhedral angle at the sides. The sectional profile of the wing model is NACA6409. The experiments on the compound wing and the rectangular wing were carried to examine different ground clearances, angles of attack, and Reynolds numbers. The aerodynamic coefficients of the compound wing were compared with those of the rectangular wing, which had an acceptable increase in its lift coefficient at small ground clearances, and its drag coefficient decreased compared to rectangular wing at a wide range of ground clearances, angles of attack, and Reynolds numbers. Furthermore, the lift to drag ratio of the compound wing improved considerably at small ground clearances. However, this improvement decreased at higher ground clearance. The drag polar of the compound wing showed the increment of lift coefficient versus drag coefficient was higher especially at small ground clearances. The Reynolds number had a gradual effect on lift and drag coefficients and also lift to drag of both wings. Generally, the nose down pitching moment of the compound wing was found smaller, but it was greater at high angle of attack and Reynolds number for all ground clearance. The center of pressure was closer to the leading edge of the wing in contrast to the rectangular wing. However, the center of pressure of the compound wing was later to the leading edge at high ground clearance, angle of attack, and Reynolds number.

scholarly journals Horizontal Wind Effect on the Aerodynamic Performance of Coaxial Tri-Rotor MAV

2020 ◽  
Vol 10 (23) ◽  
pp. 8612
Author(s):  
Yao Lei ◽  
Yiqiang Ye ◽  
Zhiyong Chen
Keyword(s):  
Wind Tunnel ◽  
Power Consumption ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Effect ◽  
Rotor Speed ◽  
Wind Tunnel Experiments ◽  
Air Vehicle ◽  
Power Loading

The coaxial Tri-rotor micro air vehicle (MAV) is composed of three coaxial rotors where the aerodynamic characteristics of is complicated in flight especially when the wind effect is introduced. In this paper, the hovering performance of a full-scale coaxial Tri-rotor MAV is analyzed with both the simulations and wind tunnel experiments. Firstly, the wind effect on the aerodynamic performance of coaxial Tri-rotor MAV is established with different rotor speed (1500–2300 rpm) and horizontal wind (0–4 m/s). Secondly, the thrust and power consumption of coaxial Tri-rotor (L/D = 1.6) were obtained with low-speed wind tunnel experiments. Furthermore, the streamline distribution, pressure distribution, velocity contour and vortex distribution with different horizontal wind conditions are obtained by numerical simulations. Finally, combining the experiment results and simulation results, it is noted that the horizontal wind may accelerate the aerodynamic coupling, which resulting in the greater thrust variation up to 9% of the coaxial Tri-rotor MAV at a lower rotor speed. Moreover, the aerodynamic performance is decreased with more power consumption at higher rotor speed where the wind and the downwash flow are interacted with each other. Compared with no wind flow, the shape of the downwash flow and the deformation of the vortex affect the power loading and figure of metric accordingly.

Numerical investigation of the aerodynamic characteristics of a train subjected to different ground conditions

2018 ◽  
Vol 232 (10) ◽  
pp. 2371-2384 ◽  
Author(s):  
Ji-qiang Niu ◽  
Xi-feng Liang ◽  
Dan Zhou ◽  
Yue-ming Wang
Keyword(s):  
Wind Tunnel ◽  
Boundary Layers ◽  
High Speed ◽  
Rapid Development ◽  
Ground Effect ◽  
Aerodynamic Performance ◽  
Detached Eddy Simulation ◽  
Scaled Model ◽  
Ground Conditions ◽  
Ground Condition

Due to the rapid development of high-speed railways and the increasing speed of trains, the aerodynamic phenomenon caused by moving trains could be affected. Therefore, the scaled model test has been widely used to simulate the aerodynamic performance of the stationary train in wind tunnel. However, it is difficult to disregard the influence of the ground effect on the aerodynamic performance of trains. In this study, the delayed detached eddy simulation based on the shear stress transport κ–ω turbulence model is used to investigate the aerodynamic performance of trains on three ground conditions (stationary floor + stationary ballast, stationary ground + stationary ballast, and stationary ballast). The numerical method used in this paper is verified by a wind tunnel test. The way the three ground conditions influence the flow field around the train is also analyzed. The results show that the ground condition affects the thickness of the ballast boundary layers without a train, thickness of the train boundary layers, train drag, distribution of pressure and velocity along the train, and the size of the wake region; however, the ground condition had a little effect on the flow structures around the train tail. These findings can help in designing the wind tunnel experiment.

scholarly journals Aerodynamics of an aerofoil in transonic ground effect: Methods for blowdown windtunnel scale testing

2012 ◽  
Vol 116 (1180) ◽  
pp. 599-620 ◽  
Author(s):  
G. Doig ◽  
T. J. Barber ◽  
A. J. Neely ◽  
D. D. Myre
Keyword(s):  
Wind Tunnel ◽  
Ground Plane ◽  
Ground Effect ◽  
Mirror Image ◽  
Navier Stokes ◽  
Oncoming Flow ◽  
Ground Clearance ◽  
Mach Numbers ◽  
Reynolds Averaged Navier Stokes ◽  
Symmetry Method

Abstract Experimental aerodynamic testing of objects in close ground proximity at high subsonic Mach numbers is difficult due to the construction of a transonic moving ground being largely unfeasible. Two simple, passive methods have been evaluated for their suitability for such testing in a small blowdown wind tunnel: an elevated ground plane, and a symmetry (or mirror-image) approach. The methods were examined using an unswept wing of RAE2822 section, with experiments and Reynolds-Averaged Navier Stokes CFD used synergistically to determine the relative merits of the techniques. The symmetry method was found to be a superior approximation of a moving ground in all cases, with mild discrepancies observed only at the lowest ground clearance. The elevated ground plane was generally found to influence the oncoming flow and distort the flowfield between the wing and ground, such that the method provided a less-satisfactory match to moving ground simulations compared to the symmetry technique.

scholarly journals Six-Component Measurements of a Model of a Wing-in-Ground Effect Craft "Marine Slider: .MU. sky" in a Low Speed Wind Tunnel.

1991 ◽  
Vol 39 (449) ◽  
pp. 314-321
Author(s):  
Toshio MATSUOKA ◽  
Akio HIGASHIDA ◽  
Takenori MATSUBARA ◽  
Nobuyuki YAMAGUCHI ◽  
Syozo KUBO
Keyword(s):  
Wind Tunnel ◽  
Ground Effect ◽  
Low Speed ◽  
Low Speed Wind Tunnel ◽  
Wing In Ground Effect

scholarly journals RESEARCH OF WING DIHEDRAL ANGLE EFFECT ON AERODYNAMIC PERFORMANCE OF TANDEM-WING UNMANNED AERIAL VEHICLE

2013 ◽  
pp. 90-101
Author(s):  
І. С. Кривохатько
Keyword(s):  
Dihedral Angle ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Theoretical Explanation ◽  
Wing Span ◽  
Induced Drag ◽  
Rear Wing ◽  
Angle Effect ◽  
Drag Ratio ◽  
Lift To Drag Ratio

In the last decade folding tube launch UAV became common, for which aerodynamic scheme "tandem" is reasonable. By the time tandem-wing aerodynamic characteristics are researched much less than ones of traditional scheme. Particularly it concerns wing dihedral angle effect on lift-to-drag ratio about which no quantitative data were found.Forward or rear wing dihedral angle appearance result in circulation redistribution and changing of rear wing induced drag. Rear wing dihedral angle effect on longitudinal aerodynamic performance of tandem-wing UAV model was researched through wind tunnel experiment. Geometry variables were forward and rear wing spans, rear wing dihedral angle and longitudinal stagger. Lift, drag and longitudinal moment coefficients were defined.The possibility of lift-to-drag ratio increasing at cruise regime was proofed. Rear wing negative dihedral angle application is able to increase maximal lift-to-drag ratio by more than 1.0 or about 10 %.It was found that wing dihedral angle effectiveness depends from relation of forward and rear wing spans and from longitudinal stagger. Longitudinal stagger increasing results in dihedral angle effectiveness falling if forward wing span is higher than rear wing. For bigger rear wing span increasing of longitudinal stagger results in dihedral angle effectiveness gaining. The hypothesis was declared that proposes theoretical explanation of experimentally founded dependencies.Also dihedral angle appearance increases lift slope because of rear wing carrying capacity gain and has almost no influence on maximal lift coefficient.All dependencies founded for rear wing negative dihedral angle are correct for forward wing positive dihedral angle except the last one is increasing longitudinal and lateral stability.

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