Impacts of grid turbulence on the side projection of planar shock waves

Abstract

In this study, the characteristics of side-projected planar shock waves propagating through grid turbulence were investigated using a counter-driver shock tube. At the location of visualization of the shock–turbulence interactions, the range of the shock Mach numbers was $$M_{\mathrm {s}} = 1.01{-}1.15$$ and the representative values of the turbulent Mach numbers $$\widetilde{M_{\mathrm {t}}}$$ were $$ 0.005{-}0.014$$ . The interaction length between the shock wave and grid turbulence was in the range approximately from $$-50$$ to $$300$$ times the integral length scale of the turbulence. For the interaction involving the strongest turbulence with $$\widetilde{M_{\mathrm {t}}} = 0.014$$ , the weakest planar shock wave with $$M_{\mathrm {s}} = 1.01$$ was largely deformed and could not be detected on the projected shadowgraph and schlieren images. The density changes on the grayscale in the projected images of the shock waves weakened and expanded multidimensionally. This undetectable profile of the shock wave could indicate that the shock wave locally lost discontinuous property change profile. The shock waves with $$M_{\mathrm {s}} \ge 1.05$$ did not show the undetectable profile in the projected image. In these cases, the projected thickness of the shock wave increased with an increase in the interaction length. The increase in the projected thickness became larger as the turbulent Mach number increased, and the shock Mach number decreased.