An interfacial region in which flow is smooth and nonturbulent. Above a surface, a laminar layer will develop and fluid velocity will increase with distance from the surface, but not indefinitely. At
some point, flow will become turbulent, with the laminar sublayer separating the turbulent layer from the surface. In the real world, most laminar boundary layers are extremely thin (order of 1 mm), but can be of biological importance, for example, next to plant leaves or as invertebrate refuges in streams.
(Also called sheet flow, streamline flow.) A flow regime in which fluid motion is smooth and orderly, and in which adjacent layers or laminas slip past each other with little mixing between them. Exch
ange of material across laminar layers occurs by molecular diffusion, a process about 106 times less effective than turbulence. Laminar flow can be easily predicted as velocity increases at a steady rate from a boundary. This contrasts with the chaotic and random nature of turbulent flow. Laminar flow is not a common occurrence in the statically neutral and unstable atmosphere and is confined to a very thin layer (1 mm) adjacent to very smooth surfaces such as snow and ice. However, in strongly statically stable regions such as the the nocturnal boundary layer, the Richardson number can be large enough that turbulence is suppressed, and the flow is laminar over a layer many tens of meters thick.
A layer in which the fluid undergoes smooth, nonturbulent flow. It is found between any surface and a turbulent layer above. See laminar boundary layer, laminar flow.