Which type of convection relies on external forces?

Forced convection relies on external forces to drive the movement of fluid and facilitate heat transfer. In this process, a pump, fan, or some other mechanical device is used to move the fluid, enhancing the heat exchange rate between the fluid and the surrounding environment or surfaces. For example, in a heating system, a fan may blow air over a heated surface to distribute warm air throughout a room more efficiently.

This contrasts with natural convection, where the movement of fluid is caused by buoyancy forces that arise from temperature variations within the fluid itself, with no external mechanical assistance. While assisted and passive convection are concepts that can relate to fluid motion as well, they do not specifically address the reliance on external mechanical forces in the same way that forced convection does.