Critical conditions for forming a detonative Mach shock from shock reflections- experiments and model development
Abstract
Irrespective of the approach taken, the outstanding question that remains to be modeled, common to both approaches, is establishing a sub-cellular model. As input, the model would have the incident shock strengths, orientations and their decay rates. As output, the model would have the ensuing shock strength of the Mach shock and its decay rate, and the fate of the shocked gases in the tongues of gas processed by the transverse waves. The model we suggest in the present work is that of Fig. 4. We isolate two incident decaying shocks in a reactive gas at conditions relevant to the cellular structure, which react at the apex of a solid obstacle. The expected reproducibility and well-posedness of the model s initial conditions make it an ideal candidate to study the reaction process in cellular detonations. The present proposed work is a sequential investigation of this model problem. Experiments are performed in a wide variety of mixtures yielding different compressibility (controlled by the ratio of specifi c heats ) and chemical sensitivities to gas dynamic perturbations. The validity of the model is then tested against the real cellular dynamics obtained in the past- We then proceed to construct approximate analytical and computational models for the process. The analytical models sought will build on triple shock collision theories, where one or multiple discontinuities are reactive. This will allow to generalize quite simply the reaction calculations of early researchers to the case where one or multiple shocks are reactive and initely thin - surprisingly a task not previously performed! The non-steady dynamics of the shocks across the reaction will be modeled using an extension of Whitham s Geometrical Shock Dynamics to account for shock decay. This will permit to obtain the shock, decay and curvature after reaction and study the ignition processes along a particle path.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 29, 2024
- Source ID
- FA95502310214
Entities
People
- Matei Radulescu
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Ottawa