ABSTRACT
This chapter discusses problems related to the study of phase objects by applying Mach–Zehnder optical classic and holographic interferometry. In regard to the holographic approach, the reconstruction schemes of studying a signal wave by using holographic Schlieren and shadow techniques were analyzed. The basic concept of the Schlieren technique is to record the deflections of diagnostic beams caused by the compressible flow under test. Schlieren photography is the most frequently applied optical visualization technique because it combines a relatively simple optical arrangement with a high degree of spatial resolution and mechanical stability. The transmission of light beams through compressible flow fields in a wind tunnel with index-of-refraction variations has been extensively studied by different Schlieren visualization techniques. Most of the published experimental works used a diagnostic beam transmitted through the flow field in the direction perpendicular to the flow axis.
