Experimental Characterization of Limit Cycle Oscillations in Membrane Wing Micro Air Vehicles

2010 ◽  
Vol 47 (4) ◽  
pp. 1300-1308 ◽  
Author(s):  
Jordan W. Johnston ◽  
Will Romberg ◽  
Peter J. Attar ◽  
Ramkumar Parthasarathy
Keyword(s):  
Limit Cycle ◽  
Micro Air Vehicles ◽  
Limit Cycle Oscillations ◽  
Experimental Characterization ◽  
Membrane Wing ◽  
Air Vehicles

A Characterization of Limit Cycle Oscillations in Membrane Wing Micro Air Vehicles at Low Angle of Attack

2010 ◽  
Author(s):  
Peter J. Attar ◽  
Jordan W. Johnston ◽  
William A. Romberg ◽  
Ramkumar N. Parthasarathy ◽  
Brian J. Morris
Keyword(s):  
Limit Cycle ◽  
Micro Air Vehicles ◽  
Element Model ◽  
Limit Cycle Oscillation ◽  
Limit Cycle Oscillations ◽  
Wing Membrane ◽  
Membrane Wing ◽  
Cycle Oscillation ◽  
Nonlinear Finite Element Model ◽  
Air Vehicles

In this paper, a (three) batten-reinforced fixed wing membrane micro air vehicle is used to determine the effect of membrane pre-strain on flutter and limit cycle behavior of fixed wing membrane Micro Air Vehicles. For each configuration tested, flutter and subsequent limit cycle oscillations are measured in wind tunnel tests and predicted using an aeroelastic computational model consisting of a nonlinear finite element model coupled to a vortex lattice solution of the Laplace equation and boundary conditions. Agreement between the predicted and measured onset of limit cycle oscillation is good as is the prediction of the amplitude of the limit cycle at the trailing edge of the lower membrane. A direct correlation between levels of strain and the phase of the membranes during the limit cycle is found in the computation and thought to also occur in the experiment.

Aeroelastic Analysis of Membrane Micro Air Vehicles

2009 ◽  
Author(s):  
Peter J. Attar ◽  
Raymond E. Gordnier ◽  
Jordan W. Johnston ◽  
William A. Romberg ◽  
Ramkumar N. Parthasarathy
Keyword(s):  
Strouhal Number ◽  
Limit Cycle ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Micro Air Vehicles ◽  
Element Model ◽  
Wing Membrane ◽  
Reduced Frequency ◽  
Membrane Wing ◽  
Air Vehicles

The fluid and structural response of two different membrane wing Micro Air Vehicles is studied through computation and experiment. A (three) batten-reinforced fixed wing membrane micro air vehicle is used to determine the effect of membrane prestrain and fixed angle of attack on flutter and limit cycle behavior of fixed wing membrane Micro Air Vehicles. For each configuration tested, flutter and subsequent limit cycle oscillations are measured in wind tunnel tests and predicted using an aeroelastic computational model consisting of a nonlinear finite element model coupled to a vortex lattice solution of the Laplace equation and boundary conditions. Correlation between the predicted and measured onset of limit cycle oscillation is good as is the prediction of the amplitude of the limit cycle at the trailing edge of the lower membrane. A direct correlation between levels of strain and the phase of the membranes during the limit cycle is found in the computation and thought to also occur in the experiment. The second membrane wing micro air vehicle configuration is that of a plunging membrane airfoil model. This model is studied computationally using a sixth-order finite difference solution of the Navier-Stokes equations coupled to a nonlinear string finite element model. The effect, on the structural and fluid response, of plunging Strouhal number, reduced frequency and static angle of attack is examined. At two degree angle of attack, and Strouhal number of 0.2, the effect of increasing the plunging reduced frequency is to decrease the sectional lift coefficient and increase the sectional drag coefficient. At this angle of attack, minimal change in the sectional lift coefficient is found when increasing from a Strouhal number of 0.2 to 0.5 at reduced frequencies of 0.5 and 5.903, the lowest and highest values of this parameter which are studied in this work. For this angle of attack the maximum change which occurs when increasing the Strouhal number from 0.2 to 0.5 is at a reduced frequency of 1.5. When the effect of angle of attack is studied, it is found that at a Strouhal number of 0.5 and reduced frequency of 1.5 the plunging flexible model demonstrates improved lift characteristics over the fixed flexible airfoil case. The greatest improvement occurs at an angle of attack of 2 degrees followed by 10 degrees and then 6 degrees. Finally the effect on the flow characteristics of airfoil flexibility is investigated by increasing the membrane pre-strain from a nominal value of 5 percent to that of 20 percent. This increase in pre-strain results in a reduced value of sectional lift coefficient as compared the 5 percent pre-strain case at the same fixed angle of attack, Strouhal number and reduced frequency.

Membrane wing aerodynamics for micro air vehicles

2003 ◽  
Vol 39 (6-7) ◽  
pp. 425-465 ◽  
Author(s):  
Yongsheng Lian ◽  
Wei Shyy ◽  
Dragos Viieru ◽  
Baoning Zhang
Keyword(s):  
Micro Air Vehicles ◽  
Membrane Wing ◽  
Wing Aerodynamics ◽  
Air Vehicles

Impact of Flexibility on the Aerodynamics of an Aspect Ratio Two Membrane Wing

2012 ◽  
Author(s):  
Raymond E. Gordnier ◽  
Peter J. Attar
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Micro Air Vehicles ◽  
Navier Stokes ◽  
Elastic Membrane ◽  
Pitching Moment ◽  
Flexible Membrane ◽  
Membrane Wing ◽  
The Impact ◽  
Air Vehicles

Development of an aeroelastic solver with application to flexible membrane wings for micro air vehicles is presented. A high-order (up to 6th order) Navier-Stokes solver is coupled with a geometrically nonlinear p-version Reissner-Mindlin finite element plate model to simulate the highly flexible elastic membrane. An implicit LES approach is employed to compute the mixed laminar/transitional/turbulent flowfields present for the low Reynolds number flows associated with micro air vehicles. Computations are performed for an aspect ratio two membrane wing at angles of attack α = 10°, 16° and 23° for a Reynolds number, Re = 24,300. Comparisons of the computational results with experimental PIV and surface deflection measurements demonstrated reasonable agreement. Reduced separation and enhanced lift are obtained due to favorable interactions between the flexible membrane wing and the unsteady flow over the wing. The impact of flexibility on the aerodynamic performance comes primarily from the development of mean camber with some further effects arising from the interaction between the dynamic motion of the membrane and the unsteady flowfield above. At lower angles of attack this lift enhancement comes at the cost of reduced L/D. The nose-down pitching moment increases with flexibility at the lowest angle of attack but is reduced for the higher two angles of attack. These results suggest that membrane flexibility might provide a means to reduce the impact of strong gust encounter by maintaining lift and reducing the effect of the gust on pitching moment.

Membrane Wing Model for Micro Air Vehicles

AIAA Journal ◽  
2003 ◽  
Vol 41 (12) ◽  
pp. 2492-2494 ◽  
Author(s):  
Yongsheng Lian ◽  
Wei Shyy ◽  
Peter G. Ifju ◽  
Erwan Verron
Keyword(s):  
Micro Air Vehicles ◽  
Wing Model ◽  
Membrane Wing ◽  
Air Vehicles

Modal Analysis of a Flexible Membrane Wing of Micro Air Vehicles

2011 ◽  
Vol 48 (6) ◽  
pp. 1960-1967 ◽  
Author(s):  
Uttam Kumar Chakravarty ◽  
Roberto Albertani
Keyword(s):  
Modal Analysis ◽  
Micro Air Vehicles ◽  
Flexible Membrane ◽  
Membrane Wing ◽  
Air Vehicles
Sign in / Sign up

Export Citation Format

Share Document