Experimental and computational study of high enthalpy double-wedge flows

A series of experiments designed to study reacting nitrogen flow over doubl e-wedge geometries was conducted in the T5 shock tunnel at the California I nstitute of Technology. These experiments were designed using computational fluid dynamics to test nonequilibrium chemistry models. Surface heat trans fer rate measurements were made, and holographic Mach-Zehnder interferometr y was used to visualize the flow Analysis of the data shows that computatio ns using standard thermochemical models cannot reproduce the experimental r esults. The computed separation zones are smaller than the experiments indi cate. However, the computed heat transfer values match the experimental dat a in the separation zone, and on the second wedge the computed heat transfe r distribution matches the shape and heights of the experimental distributi on but is shifted due to the difference In the size of the separation zones , The most likely reasons for failure of the computations to reproduce the experimental data are uncertainties in the equilibrium and nonequilibrium n itrogen dissociation rates, non-Boltzmann vibrational energy distributions in the freestream, and possible noncontinuum effects at the model leading e dge and in the shock interaction region.