Abstract
An isolated combustion spot—known as a flame ball (FB)—is considered while it is advected by a turbulent flow of a lean premixture of such a light fuel as hydrogen. A Batchelor approximation for the surrounding Lagrangian flow is made. This in principle gives one an access to the FB lifetime and to its response to the ambiant Lagrangian rate-of-strain tensor by means of a nonlinear and forced integro-differential equation for the current FB radius. For a diagonal deduced from random Markov processes of the Ornstein-Uhlenbeck type, or linearly filtered versions thereof, extensive numerical simulations and approximate theoretical analyses agree that (i) flame balls can definitely live for much longer than their time of spontaneous expansion/collapse; (ii) large enough values of are compatible with Poisson statistics; (iii) the variations of with the characteristics of mirror the latter’s statistics, more precisely that of Open problems, dealing with a nondiagonal ignition-related transients and/or collective effects, finally are evoked.
- Received 1 October 2003
DOI:https://doi.org/10.1103/PhysRevE.69.036304
©2004 American Physical Society