flowfield CFD REFERENCE

Computational fluid dynamics

Understand the equations, decide what turbulence to resolve, and see which grids and tools fit the aerodynamic question.

Compare flow methodsRun the momentum labRead Navier–StokesCompare 46 software entries

Momentum balance

Conservation form for constant density and viscosity.

∂(ρuk)∂t+∂∂xi(ρuiuk−μ∂uk∂xi)=−∂p∂xk+Fk\frac{\partial(\rho u_k)}{\partial t} +\frac{\partial}{\partial x_i}\left(\rho u_i u_k-\mu\frac{\partial u_k}{\partial x_i}\right) =-\frac{\partial p}{\partial x_k}+F_k

Equations and turbulence

Start with conservation of mass, momentum and energy. Follow what changes when you average, filter or directly resolve the flow.

Compare equations and compute effort
  1. Navier–Stokes and EulerThe conservation laws behind most aerodynamic flow solvers.
  2. RANS and turbulence closureWhat averaging does to the momentum equation and why it adds unknowns.
  3. URANSTime-dependent mean flow with a RANS turbulence closure.
  4. LES and DNSFilter the flow to resolve large eddies, or resolve down to the smallest scales.
  5. DES, DDES and IDDESHow hybrid RANS–LES methods change behavior near the wall and in separated flow.
  6. From equations to a numerical solverSeparate discretization, flux calculation and time integration from the physics model.

Meshing techniques

Compare grid topology, generation algorithms, near-wall resolution and methods for moving or adapting a mesh.

  1. Mesh families and topologyStructured, unstructured and hybrid grids serve different geometric and numerical needs.
  2. How meshes are generatedCompare mapped blocks, advancing fronts, Delaunay and Cartesian workflows.
  3. Boundary layers and y⁺Choose near-wall spacing to match the model, then check it on the solved flow.
  4. Overset grids and moving bodiesChoose how a grid represents relative motion, from blades to flap deployment.
  5. Cut cells, immersed boundaries and adaptationRepresent complex surfaces on background grids and refine where the solution needs it.
  6. Mesh quality and grid convergenceCheck whether your aerodynamic conclusions survive changes in numerical resolution.

CFD and aero software

Compare governing equations, turbulence options, specialisms, access and indicative cost.

Browse 46 entries