folyás

Folyás is the Hungarian noun for flow, referring to the movement of a substance—most commonly liquids and gases—from one place to another. The term derives from the verb folyik, “to flow.” In everyday speech it can denote the manner in which something progresses or develops over time, not only physical liquids.

In physics and engineering, folyás describes fluid motion within a container or along a channel. In hydrology it is often used as a synonym for streamflow or discharge: the volume of water that passes a given cross-section per unit time, typically expressed in cubic metres per second (m3/s). Folyás is governed by principles of conservation of mass and momentum and is influenced by factors such as velocity, depth, channel slope and roughness, and fluid properties like density and viscosity.

Flow behavior is categorized as laminar or turbulent. Laminar flow features smooth, orderly motion with low Reynolds numbers; turbulent flow is chaotic with mixing at high Reynolds numbers. Open-channel flow and pipe flow are described by different models, including Manning’s or Chezy’s formulations for gravity-driven open channels and the Navier–Stokes equations for general cases.

Beyond physical contexts, folyás can denote the flow of time, information, or processes in metaphorical use. The concept provides a common frame across disciplines for describing movement, rate, and continuity.