folyássebesség
folyássebesség, also called flow velocity, refers to the speed at which a fluid—liquid or gas—moves through a given section of a flow path. It is defined as the rate of change of the fluid's displacement with respect to time, and is typically expressed in metres per second (m/s), centimetres per second (cm/s), or litres per minute (L/min) for liquids, and in centimetres per second or inches per second for gases. The value of a flow velocity depends on the fluid’s momentum, the cross‑sectional area of the conduit or channel, and the forces acting on the fluid, such as pressure gradients, gravity, or external pumps and fans.
In engineering applications, the flow velocity is a key parameter for determining shear stress on pipe walls,
In summary, the folyássebesség is a fundamental hydrodynamic quantity that quantifies how fast a fluid traverses