NACA duct

A NACA duct, also sometimes called a NACA scoop or NACA inlet, is a common form of low-drag air inlet design, originally developed by the U.S. National Advisory Committee for Aeronautics (NACA), the precursor to NASA, in 1945.

When properly implemented, a NACA duct allows air to flow into an internal duct, often for cooling purposes, with a minimal disturbance to the flow. The design was originally called a "submerged inlet", since it consists of a shallow ramp with curved walls recessed into the exposed surface of a streamlined body, such as an aircraft. It is especially favored in racing car design.