Convective mixing particle paths

Forced convection cooling can be divided into laminar flow and turbulent flow. The transition from laminar to turbulent flow in air usually occurs at a velocity of 180 ft/min (180 Ifm). In laminar (or sfreamline) flow, the fluid particles follow a smooth, continuous path where the velocity vectors of the particles are always parallel and never intersect. The heat is transferred by molecular conduction in the fluid and by the solid-fluid interface. Tm-bulent flow, characterized by the irregular motion of fluid particles, has eddies in the fluid in which the particles are continuously mixed and rearranged. The heat is transferred in turbulent flow from the eddies back and forth across the streamlines. The greater heat transfer occurs for turbulent flow. 

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