Packet flutter and aerodynamic modes for non-homogenous airfoil cascades in highly distorted, periodic, stationary throughflows

An analytical investigation of the general flutter characteristics of periodically detuned airfoil cascades kept in periodically nonuniform basic flows is conducted under the assumption of linearized aerodynamics. The existence of certain packet flutter modes is studied, as are the specific aerodynamic modes to be used in the calculation of the aerodynamic coefficients such that the number of blade passages in the computational domain is minimized. The interpretation of the critical flutter condition for nonuniform flows is examined.