On the Disturbance Equation of Flow Instability
  In this note, we propose a new idea by analyzing the basic disturbance equations, and give starting equations for understanding the instability phenomena of laminar flows and transition to turbulence. It is considered that there is an interaction between the disturbance and the base flow in the process of disturbance amplification. The transition to turbulence is the result of this interaction. The linearity of the disturbance in linear theory is oversimplified the problem. It is pointed out that the development of disturbance is subjected to the influence of the base flow, and these effects must be included in the governing equations of the disturbance. 
Hua-Shu Dou