In automotive design, a nolder is a small aerodynamic shape (a strip, wing, protrusion, lip or profile) integral to bodywork or to an aerodynamic attachment – e.g., a spoiler, diffuser or splitter – perpendicular to the direction of air flow travel[1] for the purpose of further managing and refining air flow.
Nolders are used in both high-performance as well as in less critical aerodynamic applications.
Very soon, in addition to internal spoilers, we will begin to talk about 'nolders': these are short and thin flaps placed at the ends of the spoiler output in a position roughly perpendicular to the flow. It is a small strip placed at its maximum inclination and it allows Cz to be significantly increased when the winglets have limited dimensions.