Stability of Standing Normal Detonation Under Varying Flow Conditions

The effects of different flow conditions on the stability and structure of standing detonation waves are investigated using numerical simulations conducted with a compressible reacting flow solver with finite-rate chemistry that captures varying reaction rates over a wide range of thermodynamic conditions. Adaptive mesh refinement is applied across the detonation structure to resolve transverse waves and triple-point interactions. Standing normal detonations (SNDs) are fixed in the laboratory frame by a conical shock induced by a reduction of the cross-sectional area where shear layers downstream of the Mach stem act as an adaptive boundary, allowing the detonation to grow radially by absorbing energy from transverse waves. This flow configuration provides reduced geometric influence to study the stability and propagation of detonations, while allowing for increased data collection time and shortened geometries. The study examines three conditions to assess their effects on SND stability, with the aim of reducing the induction length and increasing the density of cellular instabilities along the reaction front. By varying the inflow conditions, different detonation modes are obtained, including a weakly cellular detonation, a spinning detonation, and a fully cellular detonation. Induction length analysis reveals cyclical decoupling of the weakly cellular detonation, which is supported by a single detonation cell, whereas the spinning and cellular detonations exhibit increased stability.