Editing Shock wave (section)

== Technological applications==
In the examples below, the shock wave is controlled, produced by (ex. airfoil) or in the interior of a technological device, like a [[turbine]].

=== Recompression shock ===
[[Image:Transonic flow patterns.svg|thumb|right|Recompression shock on a transonic-flow airfoil, at and above [[critical Mach number]] ]]
* These shocks appear when the flow over a transonic body is decelerated to subsonic speeds.
* Examples: Transonic wings, turbines
* Where the flow over the suction side of a transonic wing is accelerated to a supersonic speed, the resulting re-compression can be by either Prandtl–Meyer compression or by the formation of a normal shock. This shock is of particular interest to makers of transonic devices because it can cause separation of the boundary layer at the point where it touches the transonic profile. This can then lead to full separation and stall on the profile, higher drag, or shock-buffet, a condition where the separation and the shock interact in a resonance condition, causing resonating loads on the underlying structure.

=== Pipe flow ===
* This shock appears when supersonic flow in a pipe is decelerated.
* Examples:
** In supersonic propulsion: [[ramjet]], [[scramjet]], [[unstart]].
** In flow control: needle valve, choked venturi.
* In this case the gas ahead of the shock is supersonic (in the laboratory frame), and the gas behind the shock system is either supersonic (''oblique shock''s) or subsonic (a ''normal shock'') (Although for some oblique shocks very close to the deflection angle limit, the downstream Mach number is subsonic.) The shock is the result of the deceleration of the gas by a converging duct, or by the growth of the boundary layer on the wall of a parallel duct.

=== Combustion engines===
The [[wave disk engine]] (also named "Radial Internal Combustion Wave Rotor") is a kind of [[pistonless rotary engine]] that utilizes ''shock waves'' to transfer energy between a high-energy fluid to a low-energy fluid, thereby increasing both temperature and pressure of the low-energy fluid.

=== Memristors ===
In [[memristor]]s, under externally-applied electric field, shock waves can be launched across the transition-metal oxides, creating fast and non-volatile resistivity changes.<ref>{{Cite journal|last1=Tang|first1=Shao|last2=Tesler|first2=Federico|last3=Marlasca|first3=Fernando Gomez|last4=Levy|first4=Pablo|last5=Dobrosavljević|first5=V.|last6=Rozenberg|first6=Marcelo|date=2016-03-15|title=Shock Waves and Commutation Speed of Memristors|journal=Physical Review X|language=en-US|volume=6|issue=1|pages=011028|doi=10.1103/physrevx.6.011028|bibcode = 2016PhRvX...6a1028T |arxiv=1411.4198|s2cid=112884175}}</ref>