Instability of elliptic jets

This paper presents a detailed account of the hydrodynamic stability characteristics of the initial region of an elliptic jet. A realistic mean velocity profile is used. Calculations of growth rates, phase velocities, and eigenfunctions are presented. The growth rates of all modes in the initial mixing region are found to depend on the minimum momentum thickness. Pressure fluctuations are found to be greatest for all modes close to the major axis. An irregular normal mode is found at larger eccentricities. All modes, odd or even about the major axis and with periods of μ or 2μ, have similar growth rates in the initial mixing region.