An oblique shock is inclined relative to the upstream velocity. In an inviscid perfect gas, the normal velocity satisfies the normal-shock jump conditions while the tangential velocity is continuous.
If with and the upstream Mach number is , the shock angle is the Mach angle to leading order and the flow deflection isThe normal speed decreases, so the downstream flow turns toward the shock front.
The Mach angle of a supersonic flow with Mach number is . Infinitesimal pressure disturbances lie on the corresponding Mach cone, and a weak oblique shock approaches this angle as its strength tends to zero.
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An oblique shock is a type of shock wave that occurs in supersonic flows when the flow encounters a ramp, wedge, or other surfaces that create a change in direction. Unlike normal shocks, which are perpendicular to the flow direction, oblique shocks are inclined at an angle relative to the flow direction.