Verification and validation for laminar hypersonic flowfields, part 2: Validation

A validation methodology is applied to the laminar Mach 8 flow over a spherically blunted cone. Validation of the overall computational model is performed via surface pressure comparisons with experimental data. Careful attention is paid to the submodels in the computational simulations and the assumptions in the experimental data analysis. The computational submodels for molecular viscosity and thermal conductivity are validated by comparisons to experimental data, whereas the vibrational nonequilibrium submodel is validated by comparing to published results using the vibrational master equation. The thermodynamic state of the hypersonic wind-tunnel nozzle is examined, and arguments are made for the presence of a significant amount of vibrational nonequilibrium in the tunnel. After extensive investigation, a 1.4% error was discovered in the freestream static pressure originally reported in the experiment. Accounting for this error, along with the experimental uncertainty and estimated numerical error, agreement was found for surface pressure within 1.5%. The remaining errors are likely due to flowfield nonuniformities in the tunnel, which are estimated using tunnel pitot calibration data and the method of characteristics.