Digital interferometry application to the study hypersonic wind tunnel flows

摘要

Laser holographic interferometer was used for visualization axisymmetrical free flows at Mach number 6 in test section of the hypersonic wind tunnel. This interferometer was designed on basis of schlieren apparatus with restricted sounding beam diameter. So the visualization of full flow field including its boundaries is impossible. Such visualization is necessary for the calculation radial density distributions in accord with interferometric data. It is of interest to study the density behavior near axis, where under theoretical prediction can be taken place local perturbation of flow homogeneity. However the visualization does not reveal this perturbation. It is proposed to use for the density fields modeling the results of the theoretical calculation jets at M=6. In addition, special modeling is used for description the density perturbation near the axis. Using modeling density fields, it was realized the interferograms calculations with the aid of digital interferometry, which technology was developed by authors early. So it was defined the condition for the revealing local perturbation of flow field near axis.