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Visualization of Mechanical Processes: An International Online Journal


ISSN Online: 2152-209X

Visualization of Mechanical Processes: An International Online Journal

DOI: 10.1615/VisMechProc.v1.i2.40

Experimental investigation and mathematical simulation of unsteady aerodynamic characteristics of a transonic cruiser model at small velocities in a wide range of angles of attack

Alexander Nikolaevich Khrabrov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
Konstantin Anatolievich Kolinko
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
Yuriy Alexandrovich Vinogradov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
Anatoliy Nicolaevich Zhuk
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
Igor Igorevich Grishin
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky, Russia
Dmitry Igorevich Ignatyev
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow region, 140180 Russia

ABSTRACT

Results of experimental investigation of unsteady aerodynamic characteristics obtained at forced oscillation with various frequencies and amplitudes are considered for the model of transonic cruiser aircraft (TCR) with canard and swept wing. To measure the dynamic derivatives of the model versus angle of attack and frequency, the tests were implemented with the use of a small-amplitude forced oscillation rig. The antidamping depending on the oscillation frequency was observed in a certain range of angles of attack. The dynamic hysteresis loops of aerodynamic characteristics were studied at the model forced oscillations with large amplitudes. The traditional approach based on aerodynamic derivatives failed to take into account the model damping versus oscillation frequency in the flight dynamics problems. The traditional approach also failed to describe adequately the dynamic phenomena for pitch moment coefficient observed at oscillations with large amplitudes at the development of the flow separation. In this paper, two alternative approaches are proposed for the description of all dynamic peculiarities of the pitch moment coefficient observed in the experiment. To describe the dynamic dependence of the pitch moment coefficient, a nonlinear state-space model with an additional differential equation describing effects of the flow separation development lag is used. A neural network is proposed to be used in the second approach. Each of the approaches has its own the pros and cons.