European Turbulence Conference 14

Full Program »

Effective rates in dilute reaction-advection systems

View File

A dilute system of reacting particles transported by fluid flows is considered. The particles react as A+A -> O with a given rate when they are within a finite radius of interaction. The system is described in terms of the joint n-point number spatial density that obeys a hierarchy of transport equations. An analytic solution is obtained in either the dilute or the long-time limit by using a Lagrangian approach where statistical averages are performed along non-reacting trajectories. In this limit, it is shown that the moments of the number of particles have an exponential decay rather than the algebraic prediction of standard mean-field approaches. The effective reaction rate is then related to Lagrangian pair statistics by a large-deviation principle. Numerical simulations in a smooth, compressible, random delta-correlated-in-time Gaussian velocity field support the theoretical results.


Giorgio Krstulovic    
Laboratoire Lagrange, Observatoire de la Côte d'Azur


Powered by OpenConf®
Copyright ©2002-2013 Zakon Group LLC