Fundamentals of enhanced scalar transport in strongly oscillating and/or resonant flow fields as created by pulse combustion

In this paper, we discuss the major features of strongly oscillating flow fields as they pertain to scalar transport. The flow fields to be discussed have been created by the acoustic resonance of a pulse combustor. Discussions of the fluid-dynamic flow field in the tailpipe where the flow is in acoustic resonance, and out of the end of the tailpipe where the flow is a pulsating free jet are presented. The flow fields to be discussed are full of intriguing features that are responsible for significantly increasing the convective transport of scalars. These features are a direct result of velocity oscillations that are sufficiently large to create flow reversal. The fundamental mechanisms that cause the increased transport of mass, momentum, and energy are discussed. We end this paper with some examples of practical systems which exploit the physics described here.