Three-Dimensional Simulation of Micro Air Vehicles with Low-Aspect-Ratio Wings

2007 ◽  
pp. 377-381
Author(s):  
X.Q. Zhang ◽  
L. Tian
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Low Aspect Ratio ◽  
Dimensional Simulation ◽  
Low Aspect Ratio Wings ◽  
Air Vehicles

Three-Dimensional Simulation of Micro Air Vehicles with Low-Aspect-Ratio Wings

2007 ◽  
Vol 339 ◽  
pp. 377-381
Author(s):  
Xiao Quan Zhang ◽  
L. Tian
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Aspect Ratio ◽  
Low Reynolds Number ◽  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Wind Tunnel Experiments ◽  
Low Aspect Ratio ◽  
Dimensional Simulation

Micro Air Vehicles (MAVs) are catching more and more attentions for their broad application in civilian and military fields. Since the theories on the aerodynamics of low Reynolds number are not maturely presented and the wind-tunnel experiments cost long periods and great expenses. The numerical simulation based on computational fluid dynamics (CFD) is a good method to choose. Through three-dimensional simulation of the wings, the aerodynamic characteristics of the flows around MAVs can be easily obtained. The tip vortices produced around low-Reynolds-number and low-aspect-ratio wings can increase the lift and stall angles. The result of numerical simulation can be used as references of theory analysis and wind-tunnel experiments.

The Lift on Wings at Sonic Speeds by Means of an Electrical Resistance Analogue

1956 ◽  
Vol 60 (542) ◽  
pp. 137-139
Author(s):  
P. J. Palmer
Keyword(s):  
Aspect Ratio ◽  
Electrical Resistance ◽  
Close Agreement ◽  
Velocity Potential ◽  
Three Dimensional ◽  
Sonic Velocity ◽  
Dimensional Problem ◽  
Low Aspect Ratio ◽  
Small Incidence ◽  
Low Aspect Ratio Wings

This note shows how a pure resistance analogue can be used to find the lift on low aspect ratio wings travelling, with small incidence, at speeds close to the sonic velocity.The method is applicable to flat, twisted or cambered wings and is simple in operation; the results obtained being in close agreement with those obtained by calculations based on the same theory.The solutions given in this note are essentially those corresponding to the Jones theory, which is applicable to low aspect ratio wings at small incidence, travelling with velocity close to the sonic value. Under these conditions it has been shown that the three-dimensional problem reduces to a series of two-dimensional problems in planes perpendicular to the direction of motion. Thus the wing can be considered as a series of spanwise sections, the solution for each section, in terms of the velocity potential, being considered in turn.

scholarly journals WIND TUNNEL CALIBRATION, CORRECTIONS AND EXPERIMENTAL VALIDATION FOR FIXED-WING MICRO AIR VEHICLES MEASUREMENTS

Aviation ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 104-113
Author(s):  
Ahmed Aboelezz ◽  
Yunes Elqudsi ◽  
Mostafa Hassanalian ◽  
Ahmed Desoki
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Aspect Ratio ◽  
Low Reynolds Number ◽  
Micro Air Vehicles ◽  
Measured Data ◽  
Published Data ◽  
Low Aspect Ratio ◽  
Low Reynolds ◽  
Air Vehicles

The increase in the number of Unmanned Aerial Vehicles (UAVs) and Micro Air Vehicles (MAVs), which are used in a variety of applications has led to a surge in low Reynolds number aerodynamics research. Flow around fixedwing MAVs has an unusual behavior due to its low aspect ratio and operates at low Reynolds number, which demanded to upgrade the used wind tunnel for this study. This upgrade enables measuring the small aerodynamics forces and moment of fixed-wing MAVs. The wind tunnel used in this work is upgraded with a state of art data acquisition system to deal with the different sensors signals in the wind tunnel. For accurate measurements, the sting balance, angle sensor, and airspeed sensor are calibrated. For validation purposes, an experiment is made on a low aspect ratio flat plate wing at low Reynolds number, and the measured data are corrected and compared with published results. The procedure presented in this paper for the first time gave a detailed and complete guide for upgrading and calibrating old wind tunnel, all the required corrections to correct the measured data was presented, the turbulence level correction new technique presented in this paper could be used to estimate the flow turbulence effect on the measured data and correct the measured data against published data.

Review of self-induced roll oscillations and its attenuation for low-aspect-ratio wings

2019 ◽  
Vol 233 (16) ◽  
pp. 5873-5895 ◽  
Author(s):  
Tianxiang Hu
Keyword(s):  
Aspect Ratio ◽  
Flight Control ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Micro Aerial Vehicles ◽  
Reynolds Number Flow ◽  
Low Aspect Ratio ◽  
Aerial Vehicles ◽  
Low Aspect Ratio Wings

Micro aerial vehicles are currently receiving growing interest because of their broad applications in many fields. In their flight tests, the onset of unwanted large amplitude roll oscillations was reported, which resulted in difficulties with flight control, and this has become one of the major challenges of current micro aerial vehicles design. In this review type of article, the low Reynolds number flow characteristics of a low-aspect-ratio wing are reviewed, and the self-induced roll oscillations are discussed with special attention being payed to the interaction between the three-dimensional flow structure and wing in reciprocatively rolling motion. The roll attenuation methods are introduced via flow control approaches, which can suppress the roll oscillations effectively by manipulating the leading-edge flow separation and tip vortices of the low-aspect-ratio wings.

Cross-Wind Influence on Low Aspect Ratio Wings at Low Reynolds Numbers

2013 ◽  
Author(s):  
Amir Karimi Noughabi ◽  
Mehran Tadjfar
Keyword(s):  
Aspect Ratio ◽  
Numerical Study ◽  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Reynolds Numbers ◽  
Aerodynamic Characteristics ◽  
Low Aspect Ratio ◽  
Aspect Ratios ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

The aerodynamics of the low aspect ratio (LAR) wings is of outmost importance in the performance of the fixed-wing micro air vehicles (MAVs). The flow around these wings is widely influenced by three dimensional (3D) phenomena: including wing-tip vortices, formation of laminar bubble, flow separation and reattachment, laminar to turbulent transition or any combination of these phenomena. All the recent studies consider the aerodynamic characteristics of the LAR wings under the effect of the direct wind. Here we focus on the numerical study of the influence of cross-wind on flow over the inverse Zimmerman wings with the aspect ratios (AR) between 1 and 2 at Reynolds numbers between 6×104 and 105. We have considered cross-wind’s angles from 0° to 40° and angle of attack from 0° to 12°. The results show that lift and drag coefficient generally decrease when the angle of the cross-wind is increased.

Bio-inspired design of flapping-wing micro air vehicles

2005 ◽  
Vol 109 (1098) ◽  
pp. 385-393 ◽  
Author(s):  
K. D. Jones ◽  
C. J. Bradshaw ◽  
J. Papadopoulos ◽  
M. F. Platzer
Keyword(s):  
Aspect Ratio ◽  
Figure Of Merit ◽  
Ground Effect ◽  
Micro Air Vehicles ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Rechargeable Battery ◽  
Flight Testing ◽  
Low Aspect Ratio ◽  
Air Vehicles

AbstractIn this paper the development and flight testing of flapping-wing propelled, radio-controlled micro air vehicles are described. The unconventional vehicles consist of a low aspect ratio fixed-wing with a trailing pair of higher aspect ratio flapping wings which flap in counterphase. The symmetric flapping-wing pair provides a mechanically and aerodynamically balanced platform, increases efficiency by emulating flight in ground effect, and suppresses stall over the main wing by entraining flow. The models weigh as little as 11g, with a 23cm span and 18cm length and will fly for about 20 minutes on a rechargeable battery. Stable flight at speeds between 2 and 5ms–1has been demonstrated, and the models are essentially stall-proof while under power. The static-thrust figure of merit for the device is 60% higher than propellers with a similar scale and disk loading.

Calculation of the Rise and Pitch of a Three-Dimensional Low-Aspect-Ratio Flat Ship

1991 ◽  
Vol 35 (04) ◽  
pp. 314-324
Author(s):  
Todd McComb
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Static Case ◽  
Equilibrium Flow ◽  
Low Aspect Ratio ◽  
Fast Speed ◽  
Flow Past

Using low-aspect-ratio flat ship theory, this paper defines a procedure to determine the position of a hull which is in equilibrium at some "fast" speed in terms of a given hull shape for the same hull at rest. This procedure is then used to find the equilibrium flow past a moving ship, when given the shape of the hull at rest. The method is then extended to find the hull configuration at various speeds based on either the configuration in the static case or at some other equilibrium speed, leading to a calculation of drag versus speed. Some general formulas and some simple examples are given.

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