vane

A vane is a flat blade, plate, or small wing attached to a rotating or stationary body, used to direct, shape, or measure the movement of fluids, such as air or water, or to indicate wind direction. Common examples include weather vanes, turbine blades, and pump vanes.

A weather vane, also called a wind vane, is a device mounted outdoors on roofs or masts. It consists of a freely rotating body and a fixed directional scale; wind pressure on the vane aligns it with the wind, showing the direction from which the wind is coming. Weather vanes have a long history in agriculture and navigation and are often decorative.

In engineering, a vane refers to a blade on a rotor or stator. Vanes on impellers and turbines transfer energy between the fluid and the rotating element, shaping flow and changing pressure. Radial vanes extend outward from a central hub, while axial vanes run parallel to the axis. Some devices use guide vanes to direct or throttle flow and improve efficiency, such as in compressors, turbines, and pumps. Vane assemblies are also part of nozzles, diffusers, and ventilation systems, where precise vane angles control velocity and direction.

In mechanics and aerospace, vanes are typically made from metal or composites and are designed with specific airfoil shapes, curvatures, and angles to withstand stresses and optimize performance. The term “vane” emphasizes the blade-like component’s role in interacting with moving fluids, whether to measure, direct, or convert energy.