On Some Limitation of State-Space Models in Subsonic Unsteady Aerodynamics

• Autorzy: Nowak M.
• Konferencja: German-Polish Workshop on Dynamical Problems in Mechanical Systems (6 ; 12-18.09.1999 ; Söllerhaus , German)
• Języki publikacji: EN

Abstrakty

EN

The knowledge of linearized unsteady aerodynamic forces i. e. the aerodynamic transfer matrices related to small structural motion and gusts, is essential for stability analyses and to design of active flutter suppression and gust alleviation systems. The equations of motion of a flexible aircraft contain unsteady generalised aerodynamic force terms which when expressed in the Laplace domain, are transcendental functions. In practice, they are usually approximated with rational functions of the Laplace variable, which fit best a set of values of harmonic aerodynamic forces, calculated over a specified range of the frequency coefficients. In the paper, some analytical properties of the approximate aerodynamic transfer functions (in the subsonic range) are compared with exact results, obtained on the basis of numerical calculations. It will be shown, that there are some essential differences in the distribution of the singularities of transfer functions, which at high subsonic speeds may significantly delimit the accuracy of usual of usual approximations.

• Wydawca: Oficyna Wydawnicza Politechniki Warszawskiej
• Czasopismo: Machine Dynamics Problems
• Rocznik: 2000
• Tom: Vol. 24, No. 1
• Strony: 141--153
• Opis fizyczny: Bibliogr. 18 poz.

Twórcy

autor

Nowak M.

• Institute of Fundamental Technological Research, PAS, Świętokrzyska 21, 00-049 Warsaw, Poland