ABSTRACT
Natural or free convection occurs when a fluid is set in
motion by coming into contact with a surface of different
temperature. The motion is a result of the imbalance in
gravity and pressure forces on a fluid particle arising from
differences of density associated with the transfer of heat.
The fluid motion increases the rate of heat transfer above
the value that would be experienced in the absence of
motion. There is a close connection between how fluid
moves and how the heat is transferred within the moving
fluid. In natural convection, heat transfer drives fluid flow.
Forced convection, however, relies on fluid flow to enable
heat transfer.
