We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric H₂−O₂ gas mixture inside the bubble. We study the interaction between hydrodynamic instabilities and shock-induced reaction waves at a shock Mach number of Ma=2.83. The chosen shock strength ignites the gas mixture before the shock-focusing point, followed by a detonation wave, which propagates through the entire bubble gas. The reaction wave has a significant influence on the spatial and temporal evolution of the bubble. The misalignment of density and pressure gradients at the bubble interface, caused by the initial shock wave and the subsequent detonation wave, induces Richtmyer–Meshkov and Kelvin–Helmholtz instabilities. The growth of the instabilities is highly affected by the reaction wave, which significantly reduces mixing compared to an inert shock–bubble interaction. A comparison with two-dimensional simulations reveals the influence of three-dimensional effects on the bubble evolution, especially during the late stages. The numerical results reproduce experimental data in terms of ignition delay time, reaction wave speed and spatial expansion rate of the bubble gas. We observe only a slight divergence of the spatial expansion in the long-term evolution. ... Read more

We present numerical simulations of a reacting shock-bubble interaction with detailed chemistry. The interaction of the Richtmyer-Meshkov instability (RMI) and shock-induced ignition of a stoichiometric H2-O2 gas mixture are investigated. Different initial pressures in the range of po = 0.25-0.75 atm at a constant shock wave Mach number of Ma = 2.30 trigger different reaction wave types (deflagration and detonation). Low pressure reactions are dominated by H, O, OH production and high pressure chemistry is driven by HO2 and H2O2. The reaction wave type is crucial for the spatial and temporal evolution of the bubble. The RMI and subsequent Kelvin Helmholtz instabilities show a high reaction sensitivity. Mixing is significantly reduced by both types of reaction waves, with detonation waves showing the strongest effect. ... Read more