Near-field relaxation subsequent to the onset of oblique detonations with a two-step kinetic model
Honghui Teng, Hoi Dick Ng, Pengfei Yang, Kuanliang Wang
Abstract
Initiation of an oblique detonation wave (ODW) results in a near-field region of curved detonation wave surface, which cannot be predicted by the detonation polar theory and lacks in-depth work on its features. In this study, Euler equations coupled with a two-step kinetic model are used to simulate ODW dynamics, and then the flow structures are analyzed by examining the asymptotic decay of local surface angle. The flow/reaction coupling is quantified by a non-dimensional Damköhler number Das that is defined as the ratio of the characteristic flow and chemical reaction length along streamlines. The results demonstrate a spectrum of local strong solutions forms, which always happens when the ODW transition pattern is abrupt, but the strong solutions deviate from the isolated strong solution predicted by the polar theory. Furthermore, the abrupt transition leads to a strong peak of Das, while the smooth one leads to a bump. Various simulated cases indicate that the transition pattern becomes abrupt and the local strong solution arises when the maximum Das reaches a critical range.