High-enthalpy flows with viscous/inviscid interactions are investigated in a combined experimental and computational effort designed to assess the accuracy of air-chemistry models. New air and nitrogen experiments at high-enthalpy have been performed at the Large Energy National Shock (LENS) facility, and experimental measurements were made over doublecone models. These new experiments are examined by means of numerical simulation. The nozzle flows are simulated with computational fluid dynamics. Results from the nozzle flow simulations are compared with measurements made during the calibration runs. There is very good agreement between these measurements and the numerical predictions. Additional characterization of the free-stream is provided in terms of its composition and the vibrational state of the gas using this approach. We observe good agreement between numerical predictions and measurements over the double-cone model for the nitrogen experiments under nominal free-stream conditions, with only small discrepancies. However, agreement between simulation and measurements in air flows is not as good. There is a high level of uncertainty with regard to the free-stream specification in air. We do not see a significant improvement with simulations under computedtest section conditions.