Mach wave Mach wave In fluid dynamics, a Mach wave is a pressure wave traveling with the speed of sound caused by a slight change of pressure added to a compressible flow. These weak waves can combine in supersonic flow to become a shock wave if sufficient Mach waves are present at any location. Such a shock wave is called a Mach stem or Mach front. Thus, it is possible to have shockless compression or expansion in a supersonic flow by having the production of Mach waves sufficiently spaced ("cf." isentropic compression in supersonic flows). A Mach wave is the weak limit
Mach a Šebestová Mach a Šebestová Mach a Šebestová (in English: Mach and Šebestová or Max and Sally) is a Czech cartoon series. It was created by writer Miloš Macourek, director Jaroslav Doubrava, and animator Adolf Born. The animated characters were voiced by Petr Nárožný. The story follows the adventures of two third-year pupils and a torn off telephone receiver. The first series of 13 episodes was broadcast on Czechoslovak Television in 1982. Mach a Šebestová is one of the most popular series made for children's television programme Večerníček. The cartoon was adapted for the film "Mach, Šebestová a kouzelné sluchátko" (Max, Sally