Interaction between a Two-dimensional Nonsteady Detonation and a Blockage in a Channel

Abstract

A two-dimensional nonsteady detonation having two triple-shock structures is numerically produced in a diluted stoichiometric oxyhydrogen mixture at P₀=1.013x10⁴ Pa. The interaction between the detonation and a blockage placed in a channel is observed in terms of the attenuation of the detonation. In particular, the behavior of the detonation near the rear side of the blockage is strongly influenced by the Prandtl-Meyer expansion, i.e., the effect of retarding exothermic chemical reactions. As a result, the detonation changes to a decoupled shock wave causing a chemical reaction, when a strong interaction between a triple shock wave and the blockage occurs, viz. in particular, when one of the triple shocks is either eliminated by its collision with the front part of the blockage or weakened by its passage through the Prandtl-Meyer region. When the blockage weakly interacts with triple shocks, however, the detonation remains coupled although a slowdown occurs and a complete re-establishment is observed at about 3 channel widths behind the blockage: There happens no change in the number of triple shocks throughout the interaction process.