New Mechanism of the Aeroelastic Divergence Onsetстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 17 июля 2020 г.
Аннотация:There are two types of aeroelastic instabilities: divergence and flutter. Flutter is an oscillatory loss of stability, whereas transition to divergence occurs at zero frequency; that is, it is a static instability. A general divergence mechanism described in textbooks consists of a decrease of one of the natural frequencies down to zero due to negative aerodynamic stiffness, coalescence with its paired frequency, and (after the coalescence) transformation to one damped and one growing frequency. Most examples of this mechanism use quasi-steady aerodynamics that, at first sight, is suitable for divergence analyses because of its static nature. In this study, it is shown that, when using unsteady aerodynamics (Theodorsen theory), the analytical structure of eigenfrequencies essentially changes; namely, no frequency coalescence occurs but “structural” eigenfrequencies become damped. The divergence mode is not a continuation of a natural mode, but it separates from a continuous spectrum that exists in the aeroelastic system due to the wake behind the wing when unsteady aerodynamics is used but is absent in the quasi-steady case.