Accession Number : AD0282425

Title :   MIXED PROBLEMS FOR HIGHER ORDER HYPERBOLIC EQUATIONS

Corporate Author : HEBREW UNIV JERUSALEM (ISRAEL)

Personal Author(s) : AGMON,SHMUEL

Report Date : MAY 1962

Pagination or Media Count : 1

Abstract : DESCRIPTORS: *Boundary layer, *Jets, Fluid flow, Reynolds number, Laminar boundary layer, Frequency, Flu ter, Excitation, Noz zles, Wave characteristics, Stability, Vis cosity, Vortices.An attempt is made to explain the development of vortices in a separated boundary layer by investigating the axisymmetrical jet downstream of a special nozzle. According to stability theory, a shear profile of finite thickness is unstable against wavy disturbances of certain frequencies and wavelengths. If such wavy disturbances are present in the shear layer, it rolls up into discrete vortices according to Rosenhead's analysis. It is found that viscosity, though responsible for the formation of a shear layer, plays no significant role in the process of rolling up at high Reynolds numbers. The frequency of the natural fluctuations and the relation between frequency and wavelength for artificial excita ion have been measured; the re ults are in good agreement with the theory. (Author)

Descriptors :   *PARTIAL DIFFERENTIAL EQUATIONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE