Instabilities, Transitions and Turbulence

This article provides our perspective on the problem of active control of combustion instability. It makes no claim to complete or historically accurate survey, but attempts to put our past work in the context of existing literature. Starting with an equation for the energy of a general type of infinitesimal disturbance, we argue that the perturbation energy can be mitigated (or enhanced) by suitable addition of heat, mass, or body forces, along with species generation. We show that these principles work well in a number of simple experimental realizations, and highlight the application for a large combustion tunnel.