Computational fluid dynamics validation using multiple interferometric views of a hypersonic flowfield

The validity of the computed three-dimensional perfect-gas inviscid density field of the shock layer about a blunt body in a hypersonic argon freestream has been investigated. Mach-Zehnder interferometry was used to generate interferograms of such a flowfield produced in the T3 free-piston shock tunnel. Two-dimensional phase maps (representing line-of-sight integrated density) were produced from the interferograms using a two-dimensional Fourier transform fringe analysis method. Theoretical maps, computed from the computational fluid dynamics solution, compare extremely well with experimental maps for each of seven different viewing angles used to generate interferograms. The multiple angles remove the ambiguity associated with comparing theoretical and experimental integrated quantities. Thus, confidence can be placed in the validity of the three-dimensional density computations.