Unsteady Aerodynamics of Flapping Airfoil in Hovering Flight at Low Reynolds Numbers

Farcy, Alain
Kurtuluş, Dilek Funda
Alemdaroğlu, Hüseyin Nafiz
The major aim of flapping motion research is based on the understanding of the relation between the temporal and the spatial changes of the wake structure and the resulting instantaneous aerodynamic forces over the flapping wings. The essential physics of nonsteady airfoil problems can be observed from simplified two-dimensional experiments, and the interpretations of the behavior can be supported by theoretical or numerical models. The aim of this study is to find optimum parameters to generate maximum lift during this motion, by using numerical methods and analytical models. A great number of cases are investigated involving the changes in the parameters such as angle of attack, location of start of change of incidence, location of start of change of velocity, axis of rotation, and Re number. In addition to the instantaneous aerodynamic forces, pressure distributions and vorticity contours, the average lift and drag coefficient values are also calculated. Positive lift values along the motion are obtained for angle of attack greater than 30°. The vortices shed during the flapping motion generate the lift. A modelization program is developed by use of Duhamel integral in order to compare with DNS results.


Unsteady Aerodynamic Calculations of Flapping Wing Motion
Akay, Büşra; Alemdaroğlu, Hüseyin Nafiz; Department of Aerospace Engineering (2007)
The present thesis aims at shedding some light for future applications of μAVs by investigating the hovering mode of flight by flapping motion. In this study, a detailed numerical investigation is performed to investigate the effect of some geometrical parameters, such as the airfoil profile shapes, thickness and camber distributions and as well as the flapping motion kinematics on the aerodynamic force coefficients and vortex formation mechanisms at low Reynolds number. The numerical analysis tool is a DNS...
Low reynolds number aerodynamics of flapping airfoils in hover and forward flight
Günaydınoğlu, Erkan; Kurtuluş, Dilek Funda; Department of Aerospace Engineering (2010)
The scope of the thesis is to numerically investigate the aerodynamics of flapping airfoils in hover and forward flight. The flowfields around flapping airfoils are computed by solving the governing equations on moving and/or deforming grids. The effects of Reynolds number, reduced frequency and airfoil geometry on unsteady aerodynamics of flapping airfoils undergoing pure plunge and combined pitch-plunge motions in forward flight are investigated. It is observed that dynamic stall of the airfoil is the mai...
Experimental and numerical investigation of flow field around flapping airfoils making figure-of-eight in hover
Başkan, Özge; Alemdaroğlu, Hüseyin Nafiz; Department of Aerospace Engineering (2009)
The aim of this study is to investigate the flow field around a flapping airfoil making figure-of-eight motion in hover and to compare these results with those of linear flapping motion. Aerodynamic characteristics of these two-dimensional flapping motions are analyzed in incompressible, laminar flow at very low Reynolds numbers regime using both the numerical (Computational Fluid Dynamics, CFD) and the experimental (Particle Image Velocimetry, PIV) tools. Numerical analyses are performed to investigate the...
Laser sheet visualization for flapping motion in hover
Kurtuluş, Dilek Funda; Farcy, Alain; Alemdaroglu, Nafiz (American Institute of Aeronautics and Astronautics Inc.; 2006-12-01)
The aim of the present study is to understand the aerodynamics phenomena and the vortex topology of the highly unsteady flapping motion. Instead of the use of real insect/bird wing geometries and motions which are highly complex and difficult to imitate by an exact modeling, a simplified model is used to understand the unsteady aerodynamics and vortex formation during the different phase of the flapping motion.
Peerzada, Kifa; Kurtuluş, Dilek Funda; Department of Aerospace Engineering (2023-1-10)
The unsteady behavior of the flow around a symmetric NACA 0014 airfoil is analyzed taking into consideration an oscillating motion in a sinusoidal pure-plunge mode as well as the stationary condition. Numerical simulations are performed by incorporating the two-dimensional unsteady, incompressible Navier-Stokes equation at Reynolds number (Re) = 10^4. The flow is visualized at the following two angle of attacks: 0^° and 4^°. The flow is assumed to be laminar at this Reynolds number. Flow properties such as:...
Citation Formats
A. Farcy, D. F. Kurtuluş, and H. N. Alemdaroğlu, “Unsteady Aerodynamics of Flapping Airfoil in Hovering Flight at Low Reynolds Numbers,” 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46478.