In aerodynamics, hypersonic speeds is one that is supersonic. Since the 1970s, the term hasbeen generally supposed to refer to speeds of Mach 5 (5 times thespeed sound) and above.The hypersonic regime is a subset of the supersonic regime.
The precision of the Mach number at which a trade can be said to be flying at hypersonic speed is difficult to achieve, especially because the physical changes in the flow of air (molecular dissociation, ionization) occur at very different rates. Usually a combination ofeffects to be important "as a whole" around Mach 5. The hypersonic regime is often defined as the ramjet speed produces no net thrust.
Classification schemes Mach
Although the terms "subsonic" and "Supersonic" in the purest sense refers to verbal speeds below and above the local speed of sound, respectively, aerodynamics often use the same terms to discuss particular ranges of values Mach. This is due to the presence of a "transonicregime" around M = 1, where the approximations of the Navier-Stokes used to designsubsonic really no longer apply, the easiest of the many reasons is that the local level flowbegins to exceed M = 1, even when the free stream Mach number is below this value.
Meanwhile, the "supersonic regime" is usually used to talk about all the Mach numbers thatlinear theory can be used where, for example, the flow (air) is the chemical reaction, and where the transfer heat between the air and the vehicle can be reasonably neglected in the calculations.
The following table, the "regimes" or "ranges of Mach" refers, not "pure", the meanings of the words "subsonic" and "Supersonic."
In general, NASA defines "high" hypersonic Mach any number of 10 to 25, and re-entry speeds of something greater than Mach 25. Aircraft operating in this regime include the Space Shuttle and various planes of space development.
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