convective

Convective describes phenomena related to convection, the transfer of heat, mass, or momentum by the movement of a fluid such as a liquid or gas. Convection occurs when density differences cause fluid to rise or sink, or when an external agent drives flow.

In heat transfer, convection is a major mechanism alongside conduction and radiation. Natural (or free) convection arises from buoyancy forces due to temperature-induced density variations; forced convection results from external means such as fans or pumps. The rate of convective heat transfer depends on flow characteristics (velocity, turbulence), fluid properties (viscosity, thermal conductivity, density), and geometry. Engineers use the convective heat-transfer coefficient and dimensionless numbers like the Nusselt, Reynolds, and Prandtl numbers to analyze systems such as heat exchangers and convection ovens.

In meteorology, atmospheric convection refers to vertical air motions driven by heating of the surface, leading to cloud formation and, under sufficient instability, thunderstorms. Convection is a key process in weather and climate, and is often quantified by measures such as CAPE (convective available potential energy) and CIN.

In geophysics and astrophysics, convection occurs in planetary mantles, oceans, and stellar envelopes. Mantle convection drives plate tectonics; solar and stellar convection bring heat from interiors to outer layers and contribute to surface granulation.