NUMERICAL SIMULATION ON THE ESTABLISHMENT OF GASEOUS DETONATION

Numerical sii.iulatior^ are performed on the establishment and failure of oneand two-dimensional unsteady gaseous detonations with a two-step reversible reaction model. Though a one-dimensional Chapman-Jouguet(CJ) detonation is unstable, the numerical solution of such adetonation can be stabil ized by the inclusion of artificial diffusion in the finite-difference scheme. The decay of a one-dimensional CJ detonation may be caused by a disturbance whose strength depends on the space mesh size because it affects artificial diffusion. An attenuating one-dimensional detonation is reestablished by explosions in the induction region without any additive energies. In this process, an explosion in shock-heated or fire-heated gas is fol lowed by subsequent explosions, which strengthens the leading shock. The gases are heated successively and, finally, detonative explosion occurs. This mechanism may be important for transition to detonation. A plane CJ detonation in two-dimensional space is also unstable to disturbances. It is confirmed that the triple-shock detonation structure is essential to sustain the gaseous detonation in multidimensional space. The strength of explosion in detonation must be sufficient to generate a blast wave coupled with exothermic reaction, otherwise the tripleshock structure decays. Presented at the 9th ICODERS, Poitiers, France, July 3-8, 1983. Copyright © American Institute of Aeronautics and Astronautics, Inc., 1984. All rights reserved. ^Associate Professor, Department of Mechanical Engineering. tProfessor, Department of Aeronautical Engineering.