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{{More footnotes|date=November 2019}}
]
'''Detached shock''' is referred to situation in which shock isn't touching the body. This occurs when a ] flow is inclined to ] (boundary conditions). If the inclined angle is exceeded maximum value the ] solution to ] results into a ] of negative number. The physical implication is that there isn't a shock angle that can exist that satisfies normal shock and the boundary conditions in the same time. Thus, a ] occurs. The normal shock occur same distance from the body which depends on the ] (flow velocity and ]).


], producing a bow shock]]
⚫ == History ==


A '''bow shock''', also called a '''detached shock''' or '''bowed normal shock''', is a curved propagating disturbance wave characterized by an abrupt, nearly discontinuous, change in ], ], and ]. It occurs when a ] encounters a body, around which the necessary deviation angle of the flow is higher than the maximum achievable deviation angle for an attached ] (see detachment criterion<ref>{{Cite book |date=2007 |title=Shock Wave Reflection Phenomena |url=https://link.springer.com/book/10.1007/978-3-540-71382-1 |language=en-gb |doi=10.1007/978-3-540-71382-1|bibcode=2007swrp.book.....B |isbn=978-3-540-71381-4 |last1=Ben-Dor |first1=G. |series=Shock Wave and High Pressure Phenomena }}</ref>). Then, the ] transforms in a curved detached shock wave. As bow shocks occur for high flow deflection angles, they are often seen forming around blunt bodies, because of the high deflection angle that the body impose to the flow around it.
The detached shock has a significance in increasing the ] to movement in super sonic flow.
This phenomenon was discovered when the people try to increase the ] of airplanes and the
propeller show remarkable reduction in power above certain point which turn to shock and detached shock. This phenomenon is significant in reentry of space vehicle when the major contribution to the heating is due to normal shock (detached shock) temperature increase. The mathematical solution of this problem was found in ] that explain what physically was known since Mach discovery.


The thermodynamic transformation across a bow shock is non-isentropic and the shock decreases the flow velocity from ] velocity upstream to ] velocity downstream.
==External links==
* - Genick Bar-Meir, Ph.D.
* (]).
<!-- * : Link needs to be fixed. -->


== Applications ==
⚫ ]
The bow shock significantly increases the ] in a vehicle traveling at a supersonic speed. This property was utilized in the design of the return capsules during space missions such as the ], which need a high amount of drag in order to slow down during ].

== Shock relations ==
As in ] and ],
* The upstream ]s is lower than the downstream ].
* The upstream ] is lower than the downstream ].
* The upstream ] is lower than the downstream ].
* The upstream ] is greater than the downstream ].
* The upstream ] is lower than the downstream ].
* The upstream ] is equal to the downstream ], as the shock wave is supposed ].

For a curved shock, the shock angle varies and thus has variable strength across the entire shock front. The post-shock flow velocity and vorticity can therefore be computed via the ], which is independent of any EOS (]) assuming ] flow.<ref>{{Cite book |url=https://link.springer.com/book/9780387902326 |title=Supersonic Flow and Shock Waves |language=en}}</ref>

⚫ == See also ==
* ]
* ]
* ]
* ]

== References ==
{{Reflist}}

* {{cite book
| last = Landau | first = L.D. |author2=Lifshitz, E.M.
| title = Fluid Mechanics 2nd edition | origyear = 1959
| publisher = ] | year = 2005
| isbn = 978-0-7506-2767-2}}
* {{cite book
| last = Courant | first = R. |author2=Friedrichs, K.O.
| title = Supersonic Flow and Shock Waves | origyear = 1948
| publisher = Interscience Publishers | location = New York | year = 1956}}

]
⚫ ]

Latest revision as of 01:18, 24 August 2023

This article includes a list of general references, but it lacks sufficient corresponding inline citations. Please help to improve this article by introducing more precise citations. (November 2019) (Learn how and when to remove this message)
A blunt body fired from a gun against a supersonic flow in a wind tunnel, producing a bow shock

A bow shock, also called a detached shock or bowed normal shock, is a curved propagating disturbance wave characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density. It occurs when a supersonic flow encounters a body, around which the necessary deviation angle of the flow is higher than the maximum achievable deviation angle for an attached oblique shock (see detachment criterion). Then, the oblique shock transforms in a curved detached shock wave. As bow shocks occur for high flow deflection angles, they are often seen forming around blunt bodies, because of the high deflection angle that the body impose to the flow around it.

The thermodynamic transformation across a bow shock is non-isentropic and the shock decreases the flow velocity from supersonic velocity upstream to subsonic velocity downstream.

Applications

The bow shock significantly increases the drag in a vehicle traveling at a supersonic speed. This property was utilized in the design of the return capsules during space missions such as the Apollo program, which need a high amount of drag in order to slow down during atmospheric reentry.

Shock relations

As in normal shock and oblique shock,

For a curved shock, the shock angle varies and thus has variable strength across the entire shock front. The post-shock flow velocity and vorticity can therefore be computed via the Crocco's theorem, which is independent of any EOS (equation of state) assuming inviscid flow.

See also

References

  1. Ben-Dor, G. (2007). Shock Wave Reflection Phenomena. Shock Wave and High Pressure Phenomena. Bibcode:2007swrp.book.....B. doi:10.1007/978-3-540-71382-1. ISBN 978-3-540-71381-4.
  2. Supersonic Flow and Shock Waves.
  • Landau, L.D.; Lifshitz, E.M. (2005) . Fluid Mechanics 2nd edition. Elsevier. ISBN 978-0-7506-2767-2.
  • Courant, R.; Friedrichs, K.O. (1956) . Supersonic Flow and Shock Waves. New York: Interscience Publishers.
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