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 (crater) Mach (crater) Mach is a large lunar impact crater of the class known as a walled plain. It is located on the far side of the Moon and cannot be viewed directly from the Earth. Nearby craters of note include Joule to the northeast, Mitra attached to the western outer rim, and Henyey to the southwest. This is a prominent but eroded formation with multiple craters along the rim and interior. The crater Harvey breaks across the eastern rim, and its outer rampart spills across the interior floor of Mach. The overall shape of Mach resembles a pear, with a