Wave structure and unsteadiness of stabilized oblique detonation waves around hypersonic projectile

Unsteady combustion around spherical projectile flying into the combustible gas whose speed is over CJ detonation one is studied numerically. Simulations of 22 computational conditions using simple reaction model which assumes hydrogen-air premixed gas, are carried out with various projectile speed, diameter, and the premixed gas pressure under the axisymmetric and inviscid assumptions. The failed and stabilized oblique detonations are observed in the simulations. The stabilized oblique detonation appears in the cases when the projectile diameter is large and the gas pressure is high. For some of the failed oblique detonations, a collision of triple points is not observed. The propagating speed of the triple point is determined by the magnitude balance between the advection speed behind the incident shock and the speed of transverse wave. It is also found that the transverse wave propagates at CJ detonation speed when the advection flow behind the incident shock perpendicularly crosses the transverse wave. The stabilized oblique detonation has the bothsided propagating transverse wave. The cellular structure is observed using the piles of pressure distributions, and their sizes become irregular in larger diameters.