Definition
A shock wave that forms at an angle (less than 90°) to the direction of supersonic airflow, typically produced when supersonic air is turned into itself by a sharp leading edge or wedge-shaped surface. Across an oblique shock, pressure, density, and temperature increase, while velocity decreases — but unlike a normal shock wave, the flow remains supersonic after passing through it.
Plain English
A slanted pressure wave that forms on aircraft or engine parts moving faster than the speed of sound. The air slows down and gets denser as it crosses the wave, but it's still moving faster than sound on the other side.
Context Anchor
Seen in turbine-engine inlet and high-speed airflow discussions, especially where supersonic air is turned or compressed before entering an engine.
Derivation
‘Oblique’ comes from the Latin obliquus, meaning ‘slanting’ or ‘sideways.’ The name describes the shape: the shock wave forms at a slant to the airflow, not straight across it.
Why Pilots Care
Oblique shock waves create less drag and heat than normal shock waves, affecting supersonic performance and jet engine inlet efficiency.
Grounding Statement
Picture very fast air meeting a sharp ramp; instead of bending smoothly, the air forms a slanted shock line where it suddenly compresses and slows.
Intuition Check
Oblique does not mean vague or indirect here. It means the shock wave is angled or slanted relative to the airflow.
Example Sentence 1
The wedge-shaped inlet on the supersonic engine generates a series of oblique shock waves that slow the incoming air before it reaches the compressor.
Example Sentence 2
Mechanics checked the inlet ramps designed to generate oblique shock waves for the jet engine.