Parametric transition from deflagration to detonation: Runaway of fast flames

The paper is concerned with identification of the key interactions controlling deflagration-to-detonation transition in confined and unconfined gaseous systems. The issue of thermal runaway triggered by positive feedback between the advancing flame and the flame-driven precursor shock is revisited. Predictions of the asymptotic analysis based on small Mach number approximation are validated by numerical simulations of the pertinent dynamical model. The linkage between the thermal runaway and deflagration-to-detonation transition is substantiated. A possible way to model transition to detonation of an expanding wrinkled flame is discussed.