Investigating Holography

Experiments have investigated the usefulness of holographic interferometry as a flow visualization technique for studying supersonic flow in air inlets. A bench-scale two-dimensional supersonic (Mach 3) nozzle diffuser with plexiglass sidewalls was used to simulate inlet flow phenomena. One series of tests was performed with a rectangular tab of metal on the bottom wall of the channel to cause boundary-layer separation. A second series was run with a cone model mounted in the center of the channel. A real image technique of reconstruction was used to obtain photographs of the holographic interferograms from each test series. (Modified author abstract).