CFD is the simulation of fluids engineering systems using modeling (mathematical physical problem formulation) and numerical methods (discretization methods, solvers, numerical parameters, and grid generations, etc.).
Historically there was only Analytical Fluid Dynamics (AFD) and Experimental Fluid Dynamics (EFD).
CFD made possible by the advent of digital computer and advancing with improvements of computer resources.
Why Use CFD ?
(A) Analysis and Design
1. Simulation-based design instead of “build & test”
More cost effective and more rapid than EFD
CFD provides high-fidelity database for diagnosing flow field
2. Simulation of physical fluid phenomena that are difficult for experiments
Full scale simulations (e.g., ships and airplanes)
Environmental effects (wind, weather, etc.)
Hazards (e.g., explosions, radiation, pollution)
Physics (e.g., planetary boundary layer, stellar evolution)
(B) Knowledge and exploration of flow physics