General Introduction on Instability and Transition

Abstract

This monograph is an idiosyncratic look at the topics of research interests of the contributing authors ranging from (i) classical linear hydrodynamic instability in chapter 1; on (ii) receptivity (chapter 2); (iii) other topics of current interest on bypass transition (chapter 3) and spatio-temporal instability (chapter 4); (iv) bifurcation and nonlinear stabilization in a bluff-body flow (chapter 5) and (vi) qualitative changes in flow instability due to restricted heat transfer (chapter 6). These topics are admixtures of linear and nonlinear aspects of flow instabilities studied via analytical and computational routes. Even though in chapters 2 to 5, theoretical results are supplemented by computational results obtained by specifically developed high accuracy direct numerical simulation (DNS) techniques, in chapters 7 to 11 attention is focused on computational results obtained for combustors and combustion processes in engineering- a very specialized topic of current interest. This requires understanding complex, reacting, multiphase flows and their computations by large eddy simulation (LES). For this purpose, special attention is devoted in understanding waves in reacting flows and the role of computing errors in LES. However, over-riding all these special aspects, one needs to understand the concepts of basic fluid mechanics and fundamental principles of receptivity and instability.