In a warm front, a mass of relatively warm air pushes against a block of cooler air and is forced to flow up over it.

BBC: Turbulence ahead: Flight heads into storm's heart

When the balloon is inflated, the fragile bones of the passageways are permanently moved aside a millimeter or so to open up air and mucus flow.

FORBES: Balloon Therapy

When the water levels rise, air will be pumped into the barriers raising them up to block the tidal flow and protect the city from flooding.

CNN: New satellite data reveals sea-level rise

What goes for an airport or a bay can be scaled up to an ocean, or the air above it, and down to the flow off an aircraft's wingtip, or a ship's hull.

ECONOMIST: Lagrangian coherent structures

The wizardry in this engine is that Bentley managed to lighten up the Co2 emissions load by 15% in its engineering and physics (lighter materials and increased air flow).

FORBES: The Temptation of Driving the 2013 Bentley GT Speed