1. Irregular fluctuations occurring in fluid motions. It is characteristic of turbulence that the fluctuations occur in all three velocity components and are unpredictable in detail; however, statistically distinct properties of the turbulence can be identified and profitably analyzed. Turbulence exhibits a broad range of spatial and temporal scales resulting in efficient mixing of fluid properties. Analysis reveals that the kinetic energy of turbulence flows from the larger spatial scales to smaller and smaller scales and ultimately is transformed by molecular (viscous) dissipation to thermal energy. Therefore, to maintain turbulence, kinetic energy must be supplied at the larger scales. See Also ocean mixing. 2. Random and continuously changing air motions that are superposed on the mean motion of the air. See aircraft turbulence.