A
bow shock, also called a
detached shock, is a curved, stationary
shock waveA shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
that is found in supersonic flow past a finite body. Unlike an
oblique shockAn oblique shock wave, unlike a normal shock, is inclined with respect to the incident upstream flow direction. It will occur when a supersonic flow encounters a corner that effectively turns the flow into itself and compresses. The upstream streamlines are uniformly deflected after the shock wave...
, the bow shock is not necessarily attached to the tip of the body. Oblique shock angles are limited in formation based on the corner angle and upstream Mach number. When these limitations are exceeded, a bow shock occurs instead of the oblique shock.
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A
bow shock, also called a
detached shock, is a curved, stationary
shock waveA shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
that is found in supersonic flow past a finite body. Unlike an
oblique shockAn oblique shock wave, unlike a normal shock, is inclined with respect to the incident upstream flow direction. It will occur when a supersonic flow encounters a corner that effectively turns the flow into itself and compresses. The upstream streamlines are uniformly deflected after the shock wave...
, the bow shock is not necessarily attached to the tip of the body. Oblique shock angles are limited in formation based on the corner angle and upstream Mach number. When these limitations are exceeded, a bow shock occurs instead of the oblique shock. Therefore, bow shocks are often seen forming around blunt objects. In other words, when the needed rotation of the fluid exceeds the maximum achievable with an oblique attached shock, the shock detaches from the body; hence beyond the shock the flow-field is subsonic so the boundary condition can be respected at the stagnation point.
The bow shock significantly increases the
dragIn fluid dynamics, drag refers to forces that oppose the relative motion of an object through a fluid . Drag forces act in a direction opposite to the oncoming flow velocity...
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 reentryAtmospheric reentry refers to the movement of human-made or natural objects as they enter the atmosphere of a planet from outer space, in the case of Earth from an altitude above the "edge of space." This article primarily addresses the process of controlled reentry of vehicles which are intended...
.