Vortex Induced Mach Waves in Supersonic Jets
A supersonic jet is known as a source of remarkable noise which can become intolerable in the neighbourhood of jet engines, cutting torches and other supersonic jet producing devices. The most dangerous part of the noise is emitted in form of Mach waves. They appear inside as well as outside of the jet and are quite regular. The practically ideally expanded supersonic free jet in Figure 1 left hand side shows outside Mach waves visualized by Oertel sen.  using a differential interferometer. The Mach waves inside can best be detected by immobilisation records on moving film as shown in Figure 1 on the right hand photo with the w’-Mach waves outside, the w-Mach waves inside and outside and the w”-Mach waves inside.
KeywordsMach Number Shock Tube Vortex Pair Smoke Particle Mach Wave
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