downflow

Downflow refers to the movement of a fluid in a downward direction, typically under the influence of gravity or a favorable pressure gradient. It contrasts with upflow, where the fluid moves upward.

In meteorology, downdraft describes an intense downward current of air within a thunderstorm or tornado-producing storm. Downdrafts form when precipitation or cooled air becomes denser than its surroundings and sinks, often producing strong surface winds and gust fronts. They can contribute to microbursts and affect storm dynamics.

In engineering and industry, downflow configurations are used in gas-liquid contactors, absorbers, and scrubbers, where the gas or liquid flows downward through packed beds or trays. Downflow designs can offer uniform temperature profiles and high liquid residence times, but may require careful control of flooding and pressure drop.

Downflow cooling towers also rely on downward water flow through fill media, with air moving upward; this arrangement can influence heat transfer efficiency and drift losses.

In hydrology and geology, downflow describes downward movement of water through soil or rock, such as percolation during infiltration, downward recharge to aquifers, or drainage in hillslope processes.

See also: upflow, downdraft, convection, percolation.