Mach reflection of detonation wave on porous wall.

This article experimentally investigates the Mach reflection of gaseous detonation waves on porous wedges composed of equidistant inline square columns, focusing on how porosity and pore size affect the Mach reflection process. Using the smoked foil technique, the study finds that porous walls significantly attenuate the Mach stem’s strength and height compared to smooth walls, delay the onset of the triple-point trajectory, and reduce its angle; higher porosity and smaller pore size intensify these effects. The attenuation mechanism is attributed to alternating diffraction and reflection waves generated as the Mach stem interacts with the pores, causing momentum loss. Despite these differences, the triple-point trajectory on porous walls still exhibits localized self-similarity, satisfying the frozen limit near the wedge and the equilibrium limit farther away, though both characteristic lengths are shorter than those observed on smooth walls. Additionally, the critical wedge angle for the transition from regular reflection to Mach reflection decreases notably on porous surfaces relative to smooth ones.