One of the key problems in the nonlinear theory of the hydrodynamic stability is to determine the law of the evolution of the disturbance velocityamplitude.
求解扰动速度幅值的演化规律，是流动稳定性非线性理论的关键问题之一。
2
The velocityamplitude distributions of the oscillatory flow outside the boundary layer are measured at seven cross-sections along the horizontal, the vertical, and the bent sections respectively.
对于水平直管段上底面及下底面各三个截面，测量了边界层内振荡流速的振幅分布及相位分布。
3
The amplitude taper and phase correction are obtained by redistributing energy and changing phase velocity in different region inside the horn respectively.