Secondary Instability

Secondary instability theory deals with the stability analysis of finite-amplitude steady or quasi-steady states that resulted from an earlier primary instability. In many cases a secondary instability is a precursor of transition to turbulent flow. Consequently, secondary instability analysis is sometimes used for transition prediction. In this chapter we will mainly cover the theoretical framework of secondary instability analysis. The role of secondary instabilities in the transition process of various shear flows will be discussed in Chapter 9.