Glossary

16 CFD terms · quick reference.

CFLwiki ↗

Courant–Friedrichs–Lewy condition. Stability bound for explicit time integration.

DNS

Direct Numerical Simulation. Resolves all turbulence scales directly.

EOS

Equation of State. Closure relation p = f(ρ, e).

HLLC

Harten–Lax–van Leer Contact. Approximate Riemann solver that captures contact discontinuities.

Kolmogorov

Smallest scale in the turbulence energy cascade. η = (ν³/ε)^(1/4).

LES

Large Eddy Simulation. Resolves large vortices, models sub-grid scales.

Machwiki ↗

Flow speed divided by sound speed. Indicates compressibility and shock formation.

OpenFOAMwiki ↗

Open-source CFD library based on finite volume method.

PISO

Pressure Implicit with Splitting of Operators. Efficient for transient flows.

RANS

Reynolds-Averaged Navier–Stokes. Time-averaged form for turbulence modeling.

Reynoldswiki ↗

Ratio of inertial to viscous forces. Determines laminar–turbulent transition.

Riemannwiki ↗

1-D initial discontinuity problem between two states. Foundation of numerical fluxes in CFD.

SIMPLE

Semi-Implicit Method for Pressure-Linked Equations. Incompressible pressure–velocity coupling.

TVD

Total Variation Diminishing. Monotonicity condition preventing spurious oscillations.

VOF

Volume of Fluid. Tracks volume fractions of each phase in multiphase flow.

WENO

Weighted Essentially Non-Oscillatory. High-order non-oscillatory reconstruction near shocks.