Computational fluid dynamics relies on the use of computers to solve the equations that describe the motion of fluids, i.e., both liquids and gases. The equations that govern the motion of a fluid are based on the principles of conservation of mass, momentum and energy, and are familiar to most people in the form of the Navier-Stokes equations.

In engineering applications, CFD encompasses a broad spectrum of physical processes ranging from the flow around automobiles and airplanes to fluid-structure interaction and manufacturing processes such as mold filling. Typically flow simulations are characterized as either compressible or incompressible due to the differences in the governing equations and concomitant solution procedures for each flow regime. Compressible flows, as the name implies, typically involve gases where compressible effects such as shocks are considered important. In contrast, the incompressible flow (low-Mach number) regime encompasses problems that range from atmospheric dispersal to food processing, aerodynamic design of automobiles, and manufacturing processes such as chemical vapor deposition, mold filling and casting.

Using LS-DYNA:  Figure 1.  Snapshot in time showing the pressure-field during a vortex-shedding cycle for a Re=10,000 flow past the MIT hydrofoil (a NACA series 16 airfoil).

Using LS-DYNA: Figure 1a.  Snapshot in time showing the vorticity field during a vortex-shedding cycle for a Re=10,000 flow past the MIT hydrofoil (a NACA series 16 airfoil).