Experimental study on the shock wave structure and cell characteristics of oblique detonation induced by high-speed projectiles

Oblique detonation propulsion is a promising technology for hypersonic flight, and understanding the structure and propagation characteristics of oblique detonation waves is of critical importance. In this study, experimental investigations were conducted on oblique detonation waves induced by high-speed spherical projectiles using the hydrogen-oxygen detonation driven two-stage light gas gun. The shock wave structures and transverse wave propagation processes were measured and analyzed using laser shadowgraphy and soot foil techniques. Under varying initial conditions, two typical oblique detonation wave structures were observed: stabilized oblique detonation waves and bow-shaped oblique detonation waves. Measurements of the cellular structures revealed three distinct cell morphologies along the detonation front: triangular, diamond-shaped, and pentagonal. Analysis of the transverse wave characteristics indicated that the cell width of the stabilized oblique detonation wave is comparable to that of the corresponding normal detonation wave under the same initial conditions, but with significantly higher transverse wave propagation velocities. In contrast, the transverse wave size of the bow-shaped oblique detonation wave was significantly reduced due to the preheating effect of the bow shock on the combustible gas. These findings provide experimental insights into the structural diversity and dynamic behavior of oblique detonation waves under projectile-induced conditions, contributing to the fundamental understanding of hypersonic detonation phenomena.