Gravity wave

Do not confuse with gravitational wave.
In fluid dynamics, gravity waves are waves generated in a fluid medium or at the interface between two mediums (e.g. the atmosphere or ocean) which has the restoring force of gravity or buoyancy.

Other websites
 Gallery of cloud gravity waves over Iowa
 Time-lapse video of gravity waves over Iowa
 Water Waves Wiki 

Category:Fluid mechanics
Category:Atmosphere