 Forced convection

Heat-carrying fluid motion dominated by an externally imposed flow or shear. Buoyancy may still influence it; forced and free contributions can coexist. In surface-layer scaling, $z\ll |{\ell }_O|$ is predominantly shear-driven, while $z\gg |{\ell }_O|$ is predominantly buoyancy-driven for lower-boundary heating.

Forced convection is a heat transfer process that occurs when a fluid (liquid or gas) is forced to flow over a surface or through a medium, typically by mechanical means such as a fan, pump, or blower. This flow enhances the heat transfer between the fluid and the surface because it increases the fluid velocity, which in turn enhances the convection heat transfer coefficient.