Unsteady flowfields around airfoils oscillating in pitch and associated dynamic stall phenomena are inves-tigated. A viscous flow analysis and a simplified vortical flow analysis, both based on an integro-differentialformulation of the Navier-Stokes equations are developed and calibrated. The formulation of the viscous flowanalysis confines computations only to the viscous flow zone and leads to an efficient zonal solution procedure.In the simplified vortical flow analysis, computational demands are greatly reduced by partial analytic eval-uations. Simulated flowfields and computed aerodynamic loads are in good agreement with available experi-mental data.


Computational study of flapping airfoil aerodynamics
Tuncer, İsmail Hakkı (American Institute of Aeronautics and Astronautics (AIAA), 2000-05-01)
Unsteady, viscous, low-speed flows over a NACA 0012 airfoil oscillated in plunge and/or pitch at various reduced frequency, amplitude, and phase shift are computed. Vortical wake formations, boundary-layer flows at the leading edge, the formation of leading-edge vortices and their downstream convection are presented in terms of unsteady particle traces. Flow separation characteristics and thrust-producing wake profiles are identified. Computed results compare well with water tunnel flow visualization and fo...
On the wake pattern of symmetric airfoils for different incidence angles at Re=1000
Kurtuluş, Dilek Funda (SAGE Publications, 2016-06-01)
In the current study, numerical simulations are performed in order to investigate effects of incidence angle and airfoil thickness on alternating vortex pattern of symmetric airfoils at Re = 1000. This alternating vortex pattern is found to be significantly varying in shape as the incidence angle increases. The results are obtained with 1 degrees increment from 0 degrees to 41 degrees and then with 10 degrees increment from 40 degrees until 180 degrees. The instantaneous and mean vortex patterns are investi...
Mathematical model development of the anti torque system of a notar helicopter
Bakır, Hüseyin Murat; Yavrucuk, İlkay; Department of Aerospace Engineering (2008)
The anti-torque mechanism of a NOTAR helicopter is a complex system including vertical tail and pressurized tail boom which provides air ejection used for both circulation control around the boom and creating directed jet air at the end of the boom. This thesis targets the modeling of this mechanism and integrating it to a helicopter simulation model. Flight tests are performed on the MD 600N helicopter to verify the results. Finally, the simulation is compared with flight test data.
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...
Numerical simulation of fore and aft sound fields of a turbofan
Özyörük, Yusuf (American Institute of Aeronautics and Astronautics (AIAA), 2004-10-01)
A framework for predicting fan related noise from high bypass ratio engines is presented. The methodology accounts for both fore and aft radiation and includes the effects of liner treatment on the engine walls. Solutions are obtained through a combination of Euler and linearized Euler solvers, coupled with a Kirchhoff formulation for far-field noise prediction. The nacelle region is solved using the Eider solver, whereas the linearized Euler solver is used for the fan exhaust stage. Switching to the linear...
Citation Formats
İ. H. Tuncer and C. WANG, “THEORETICAL AND NUMERICAL-STUDIES OF OSCILLATING AIRFOILS,” AIAA JOURNAL, pp. 1615–1624, 1990, Accessed: 00, 2020. [Online]. Available: