gasdynamische

Gas dynamics, known in Dutch as gasdynamiek, concerns the motion of gases and the associated changes in density, pressure and temperature; the attributive form gasdynamische is used for related concepts. It deals with compressible flows, often at high speeds where density variations cannot be neglected. The fundamental governing equations are the conservation laws: mass (continuity), momentum (Navier–Stokes or Euler), and energy, together with an equation of state (typically the ideal gas law for many problems). In many problems the viscous terms can be neglected, yielding inviscid flow approximations.

Key concepts include Mach number and the classification of flows as subsonic, transonic, or supersonic; isentropic relationships; stagnation properties; shock waves (normal and oblique) and expansion fans; nozzle and diffuser theory; and one-dimensional duct flow. Gas dynamics also examines boundary-layer interactions, turbulence, and real-gas effects when temperatures are high or chemical reactions occur.

Applications span aerospace propulsion (aircraft engines and rocket nozzles), high-speed wind tunnels, gas pipelines, combustion systems and turbomachinery, as well as astrophysical contexts such as stellar winds and accretion flows. It also plays a crucial role in atmospheric reentry studies and vacuum-system design.

Methods used in gas dynamics include analytical solutions for simplified problems, computational fluid dynamics (CFD) for complex geometries, and experimental techniques such as schlieren or shadowgraph imaging. Challenges arise from real-gas behavior, chemical kinetics, radiative transfer, and turbulence modeling.