Journal of Fluid Mechanics



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A numerical study of detonation diffraction


MARCO ARIENTI a1 and J. E. SHEPHERD a2
a1 United Technologies Research Center, East Hartford, CT 06108, USA
a2 Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA 91125, USA

Article author query
arienti m   [Google Scholar] 
shepherd je   [Google Scholar] 
 

Abstract

An investigation of detonation diffraction through an abrupt area change has been carried out via a set of two-dimensional numerical simulations parameterized by the activation energy of the reactant. Our analysis is specialized to a reactive mixture with a perfect gas equation of state and a single-step reaction in the Arrhenius form. Lagrangian particles are injected into the flow as a diagnostic tool for identifying the dominant terms in the equation that describes the temperature rate of change of a fluid element, expressed in the shock-based reference system. When simplified, this equation provides insight into the competition between the energy release rate and the expansion rate behind the diffracting front. The mechanism of spontaneous generation of transverse waves along the diffracting front is carefully analysed and related to the sensitivity of the reaction rate to temperature. We study in detail three highly resolved cases of detonation diffraction that illustrate different types of behaviour, super-, sub- and near-critical diffraction.

(Published Online April 1 2005)
(Received March 10 2003)
(Revised October 15 2003)



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