Radulescu Gasdynamics Laboratory

.. and onto a PhD. Numerical Simulations of Detonation Re-Initiation Behind an Obstacle by She-Ming Lau-Chapdelaine  This numerical study explored the mechanisms responsible for the re-initiation of a detonation, which quenched while diffracting over a half-cylinder obstacle. The purpose of the study was to make accurate predictions of when detonation re-initiation would occur, determine the role various re-initiation mechanisms, and compare the effect of different chemical models. The problem was modelled using the reactive Euler equations with either the one-step Arrhenius or two-step chain-branching chemical models, calibrated to post-shock conditions in order to properly reproduce the ignition delay. The simulations were validated using the stoichiometric methane-oxygen experiments of Bhattacharjee et al. Detonation failure and separation into shock-flame structure The numerical model was able to accurately predict detonation re-init...

Nick was also nominated for some fancy award - en route for the Sirmas instability and a promising PhD.   Shock Instability in Gases Characterized by Inelastic Collisions  by Nick Sirmas The current study addresses the stability of shock waves propagating through dissipative media, analogous to both granular media and molecular gases undergoing endothermic reactions. In order to investigate the stability, a simple molecular dynamics model was developed to observe shock waves and their structures with the inclusion of energy dissipation. For this, an Event Driven Molecular Dynamics model was implemented in a 2D environment, where a molecule is represented by a disk. The simulations addressed the formation of a shock wave in a gas by the sudden acceleration of a piston. Inelastic collisions were assumed to occur only if an impact velocity threshold is surpassed, representing the activation energy of the dissipative reactions. Parametric studies ...