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The most common way to produce an oblique shock wave is to place a wedge into supersonic, compressible flow. Similar to a normal shock wave, the oblique shock wave consists of a very thin region across which nearly discontinuous changes in the thermodynamic properties of a gas occur. While the upstream and downstream flow directions are ...
In fact, correct capturing and detection of shock waves are important since shock waves have the following influences: (1) causing loss of total pressure, which may be a concern related to scramjet engine performance, (2) providing lift for wave-rider configuration, as the oblique shock wave at lower surface of the vehicle can produce high ...
The compressed flow is alternately expanded by Prandtl-Meyer expansion fans, and each "diamond" is formed by the pairing of an oblique shock with an expansion fan. When the compressed flow becomes parallel to the center line, a shock wave perpendicular to the flow forms, called a normal shock wave or Mach disk.
The figure shows one such ideal expansion fan. A supersonic expansion fan, technically known as Prandtl–Meyer expansion fan, a two-dimensional simple wave, is a centered expansion process that occurs when a supersonic flow turns around a convex corner. The fan consists of an infinite number of Mach waves, diverging from a sharp corner. When a ...
An analogous effect is encountered in the expansion around rarefactive ramps: for suitable thermodynamic conditions, the Mach number downstream of the ramp can be lower than the one upstream. [20] By contrast, in oblique shock waves, the post-shock Mach number can be larger than the pre-shock one. [21]
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 of an oblique shock wave where time averages of flow quantities don't change (a normal shock is the other limit).
Shock is formed due to coalescence of various small pressure pulses. Sound waves are pressure waves and it is at the speed of the sound wave the disturbances are communicated in the medium. When an object is moving in a flow field the object sends out disturbances which propagate at the speed of sound and adjusts the remaining flow field ...
Then a laminar boundary layer will be developed at the leading edge of the plate. And as there are viscous boundary layer, the plate will have a fictitious boundary layer so that a curved induced shock wave will be generated at the leading edge of the plate. The shock layer is the region between the plate surface and the boundary layer.