viszkózatlan

Viszkózatlan is a term used in physics and engineering to describe a fluid or medium in which viscosity is neglected. In English, the equivalent term is inviscid. It denotes an idealization in fluid dynamics where the viscous stresses are ignored, so there is no viscous dissipation. This concept is commonly applied to analyze flows where inertial effects dominate and the influence of internal friction is assumed negligible.

In mathematical modeling, viszkózatlan (inviscid) flow leads to the Euler equations rather than the full Navier–Stokes equations. The absence of the viscous term implies that the fluid has no internal friction, and vorticity behaves according to the ideal-fluid assumptions. Inviscid flows are often associated with potential flow, where the velocity field is irrotational and solutions can be found more easily. However, real fluids always possess some viscosity, so inviscid models are approximations.

In practice, viszkózatlan models are useful as outer-flow approximations in high-Reynolds-number problems or for gaining qualitative insight. They are commonly used in aerodynamics and hydrodynamics to understand pressure distributions, lift, and general flow patterns away from boundaries. Near solid surfaces, however, viscous effects become important, and boundary-layer theory or full viscous simulations (Navier–Stokes) are required to capture heat transfer, drag, and energy dissipation.

See also: inviscid flow, Euler equations, potential flow, boundary layer theory, Reynolds number, viscosity. In Hungarian terminology, the term is used as viszkózatlan közeg or viszkózatlan folyadék.