Accession Number : AD0605577

Title :   SUPERSONIC FLUTTER OF A CYLINDRICAL SHELL. I. GENERAL THEORY,

Corporate Author : THOMPSON RAMO WOOLDRIDGE INC LOS ANGELES CALIF

Personal Author(s) : Miles,John W.

Report Date : 19 AUG 1955

Pagination or Media Count : 8

Abstract : The equations governing the generation of traveling waves along an infinite, thin, cylindrical shell by an external air stream are formulated. The subsidiary problems of transverse wave propagation along the free shell and the calculation of the aerodynamic forces associated with a given wave then are solved. It is found that the minimum wave speed for the free shell occurs at a wavelength of the order of the geometric mean of shell thickness and radius. This neighborhood, in which flexural and extensional stresses are approximately equal in magnitude, is anticipated as the most critical for panel flutter (unstable wave motion). The restriction to wavelengths that are short compared with both length and radius of shell permits a relatively simple, quasi-planar approximation to the aerodynamic forces. The stability boundary for panel flutter in the absence of external damping is calculated and numerical results presented for shell thickness/radius ratio vs. Mach number. The negative damping ratio for unstable motion than is calculated and plotted vs a dimensionless dynamic pressure. It is shown that the structural damping ratio required to prevent panel flutter is equal to this negative damping ratio. (Author)

Descriptors :   (*FLUTTER, CYLINDRICAL BODIES), (*SUPERSONIC FLOW, CYLINDRICAL BODIES), MECHANICAL WAVES, VELOCITY, STRESSES, DAMPING, SURFACE PROPERTIES, AERODYNAMIC CHARACTERISTICS, LAMINAR BOUNDARY LAYER, TURBULENT BOUNDARY LAYER, AERODYNAMIC CONFIGURATIONS, THICKNESS, EQUATIONS, THEORY, SHELLS(STRUCTURAL FORMS)

Distribution Statement : APPROVED FOR PUBLIC RELEASE