Hysteresis of the aerodynamic characteristics of NACA 0018 airfoil at low subsonic speeds
D.A. Alieva, K.A. Kolinko, A.N. Khrabrov
Central Aerohydrodynamic Institute, Zhukovsky, Russia
Keywords: aerodynamic experiment, NACA 0018 airfoil, flow separation, hysteresis of aerodynamic characteristics, phenomenological mathematical model
Abstract
Results of an experimental study of the hysteresis of aerodynamic characteristics of NACA 0018 airfoil in the T-124 low-turbulent wind tunnel of low subsonic speeds of TsAGI are reported. The experiments were carried out on the OVP-124 dynamic setup under steady-state conditions with a quasi-static (continuous) increase and decrease of the angle of attack and with forced oscillations of the model over pitch with different amplitudes and frequencies relative to various set angles of attack. In all cases, measured aerodynamic characteristics exhibits a hysteresis related with the presence of a range of attack angles in which stable, non-unique separated-flow structures are observed. On the basis of experimental data obtained, a new approach to the mathematical modeling of the phenomenon of static and dynamic hysteresis of aerodynamic characteristics is developed for use in dynamics problems.
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