Rarefied hypervelocity separated flow in the transitional to continuum regimes. The transition regime for low-density flows is a no-man's-land between free-molecular and continuum flow, where the flow behaves differently to the assumptions typically used for modelling either flow type. Bird's direct Simulation Monte Carlo (DSMC) method is typically thought to be the best way of modelling these flows, but has not produced excellent agreement with previous experiments on low-density separated flow ....Rarefied hypervelocity separated flow in the transitional to continuum regimes. The transition regime for low-density flows is a no-man's-land between free-molecular and continuum flow, where the flow behaves differently to the assumptions typically used for modelling either flow type. Bird's direct Simulation Monte Carlo (DSMC) method is typically thought to be the best way of modelling these flows, but has not produced excellent agreement with previous experiments on low-density separated flows, due to computational limitations and lack of knowledge of the flow's internal energy. This proposal is a blind test of the best current DSMC codes against our experiments and a hypersonic continuum code, with the full internal energy state of the flow experimentally quantified for the first time.Read moreRead less