turbulence

Turbulence (or turbulent flow) is chaotic flow of a fluid. It is characterized by changes in flow velocity and pressure over space and time, and eddies, i.e., circular or swirling flows, often lasting only a short time. In contrast, a laminar flow has the fluid flowing in an organized fashion, potentially continuously. Turbulence in Earth atmosphere is of interest to astronomers because it is a contributor to seeing issues, and is a target of adaptive optics (AO). Turbulence also is a factor within the gas of some astronomical objects e.g., within stars or clouds: one means of detecting it is through analysis of spectral lines.