Computational fluid dynamics

Computational fluid dynamics - Wikipedia, the free encyclopedia: "Computational fluid dynamics
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Computational fluid dynamics (CFD) is the use of computers to analyze problems in fluid dynamics.
The most fundamental consideration in CFD is how one treats a continuous fluid in a discretized fashion on a computer. One method is to discretize the spatial domain into small cells to form a volume mesh or grid, and then apply a suitable algorithm to solve the equations of motion (Euler equations for inviscid, and Navier-Stokes equations for viscid flow). In addition, such a mesh can be either irregular (for instance consisting of triangles in 2D, or pyramidal solids in 3D) or regular; the distinguishing characteristic of the former is that each cell must be stored separately in memory. Lastly, if the problem is highly dynamic and occupies a wide range of scales, the grid itself can be dynamically modified in time, as in adaptive mesh refinement methods more... http://en.wikipedia.org/wiki/Computational_Fluid_Dynamics
If one chooses not to proceed with a mesh-based method, a number of alternatives exist, notably :
smoothed particle hydrodynamics, a Lagrangian method of solving fluid problems,
Spectral methods, a technique where the equations are projected onto basis functions like the spherical harmonics and Chebyshev polynomials
Lattice Boltzmann methods, which simulate an equivalent mesoscopic system on a Cartesian grid, instead of solving the macroscopic system (or the real microscopic physics).
It is possible to directly solve the Navier-Stokes equations for laminar flow cases and for turbulent flows when all of the relevant length scales can be contained on the grid (a Direct numerical simulation). In general however, the range of length scale"