Flow fields around configurations like airplanes, space planes, missiles, helicopters etc. or through technical devices like pipes, pumps, inlets of propulsion systems, turbo machinery, ram- and scramjets etc. are defined by their individual initial and boundary conditions. Generally, the system of Navier-Stokes equations is parabolic-hyperbolic in space and time and elliptic-parabolic for steady flow. The time dependent Euler equations are purely hyperbolic in time. Typically, for hyperbolic and parabolic problems Initial value problemBoundary value probleminitial boundary value conditions are imposed, whereas for elliptic problems, values on the boundaries of the flow domain determine the solution.