FIRST ORDER FREQUENCY EFFECTS IN SUPERSONIC PANEL FLUTTER OF FINITE CYLINDRICAL SHELLS.
CALIFORNIA UNIV BERKELEY DIV OF AERONAUTICAL SCIENCES
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The flutter boundary of a thin cylindrical shell of finite length is determined with the aerodynamic load obtained by linearized potential theory. A low frequency approximation is applied, together with some other plausible approximation, to circumvent the difficulty in evaluating a complicated convolution integral containing Bessel functions. Galerkins method is then used to set up an eigenvalue problem equivalent to the resulting integro-differential equation. The flutter boundary, for given Mach number and circumferential mode n, corresponds to the shell thickness ratio at which the real part of any one of the eigenvalue first become non-negative. Some interesting conclusions can be drawn, at least qualitatively, through Hadamards well known theorem on the regularity of a matrix. In particular, it is found that the most feasible circumferential mode of vibration occurs around n7. Author
- Fluid Mechanics