Experimental analysis of shock stand-off distance over spherical bodies in high-enthalpy flows

The shock stand-off distance for basic spherical models was investigated in the flow regime of 1-2km/s, a range for which data are unavailable in the open literature. Experiments were conducted on two hypersonic shock tunnels, at five different enthalpy conditions and two types of test gas, and the bow shock was captured using schlieren flow visualization technique. These results were compared with existing empirical relations and a good match was observed. To further corroborate the results, a computational analysis of the same problem was carried out using an in-house computational fluid dynamics code, HiFUN (High Resolution Flow Solver on UNstructured meshes), and the results were again seen to match well with the experiments. The shock stand-off distance is an important parameter for the design of high-speed airplanes, and therefore a solid quantitative understanding of this parameter is vital for all flow regimes. This paper aims to fill in the gap by investigating one of those regimes where available data are currently missing