摘要：

The problem of finite-amplitude instability of plane parallel flows with respect to wave-like disturbances is formulated as a search for time-periodic secondary solutions of the Navier-Stokes equations. At a certain Reynolds number Re, the secondary solution is characterized by an amplitude A, wave number alpha, and a phase velocity c in the streamwise direction. A process is investigated which should generate a neutral surface that separates the regions of stability and instability in the Re, alpha, A-space. Spectral methods in the cross-stream coordinate are used to find the neutral solution. As a test case, the neutral surface for a plane Poiseuille flow is calculated with up to four Fourier modes.

展开