laminar flow

Laminar is a term used by hydrologists, river scientists, rafters, and other experienced river watchers to describe the smooth and even flow of a river unimpeded by rocks, trees, or other obstructions. This condition is as close as a river can come to the laminar flow used by physicists in their description of all fluids: a state in which all particles move in the same direction, perfectly in parallel. Some textbooks liken the flow to layers of playing cards sliding over each other. In a river, a rock, hole, or sudden narrowing of channel width can cause more complicated flow structures, such as vortices and eddies, to form. Particles begin to move in different directions. When this occurs, laminar flow is no longer present, and the flow begins to be described as turbulent.

Lan Samantha Chang