HIFiRE-1 Boundary Layer Transition Experiment Design

*† ‡ § ** The HIFiRE (Hypersonic International Flight Research and Experimentation) project will develop and demonstrate fundamental hypersonic technologies deemed critical to the realization of next generation aerospace weapon systems. Flight one focuses primarily on integration of instrumentation on the test vehicle, with application to future flights. Boundary layer transition has been chosen as one aerodynamic parameter to measure in order to assess instrumentation performance. Analysis has been performed to place requirements on the payload. Results show that the temperature of the aeroshell is relatively benign, easing temperature requirements on transducers. Reynolds number on the vehicle is relatively low, making it marginal for smooth-body boundary layer transition. Roughness must be placed on the vehicle to ensure transition and to obtain rough-wall data. I. Introduction The HIFiRE (Hypersonic International Flight Research and Experimentation) project will develop and demonstrate fundamental hypersonic technologies deemed critical to the realization of next generation aerospace weapon systems. The research effort will consist of a series of focused tasks to resolve hypersonic phenomena through validation of computational analysis; comparison with performance predictions, enhancement of design data bases; and development of correlations with ground test. Each research effort will culminate with a flight experiment to be launched to representative flight conditions (Reynolds number and Mach) employing low cost sounding rockets. The primary objective of flight one is to determine the feasibility of applying high-bandwidth instrumentation to aerothermal flight measurements for short duration hypersonic flights at Mach numbers up to eight. The experiment will determine the suitability and survivability of multiple instrumentation types in this environment. The experiment will be incorporated into the nose cone of a Terrier-Orion launch vehicle. This paper will refer to the nose cone as the “payload. ” The measurement of three aerothermal phenomena will serve to assess the performance of the instrumentation. These sub-experiments are, in order of priority, boundary layer transition (BLT), turbulent separated shock boundary layer interaction (SBLI), and optical measurement of mass capture (OMC) in a duct. Measurement of these phenomena will serve as secondary objectives of the experiment. This paper describes analysis related to the BLT experiment to determine requirements for flight one. Boundary layer transition has an important impact on hypersonic vehicle aerodynamics and aerothermodynamics. It is an inherently challenging problem due to its nonlinear nature and sensitivity to initial and boundary conditions. Ground test of boundary layer transition is generally unsatisfactory due to the high noise levels of ground facilities compared to flight. Computation is challenging since it requires resolution of instabilities of relatively high wavenumber and frequency over large spatial domains. Flight provides the best environment for measuring transition. Instrumentation for the flight environment however, is challenging. The highest level of validation for transition prediction requires high bandwidth instrumentation. The current tests will explore the use of high-bandwidth instrumentation for flight measurement of transition. Careful measurement and computation of boundary conditions will provide added value in interpreting the data. Data from numerous past flight tests of supersonic and hypersonic transition exist. Schneider 1 offers a detailed review of transition flight tests. Vehicles were frequently thin-skin models. Backface thermocouples monitored transition, and heat transfer rates were inferred by lumped-capacitance heating models. Transition criteria based on