Holographic Interferometry on the High Enthalpy Shock Tunnel in Göttingen (HEG)

A holographic interferometer for the high enthalpy shock tunnel, HEG, is described. The system relies on recording a flow and a no-flow hologram on a thermoplastic film allowing reconstruction of each beam and thus the interferogram after an HEG run. From this interferogram it is possible to extract the shock shape around an aerodynamic model mounted in the test section and also the density distribution between the shock and the model. Results of initial tests on HEG are presented.