A building-block approach is followed in performing the validation assessment for a complex system such as an aircraft inlet. The approach consists of phases involving successively more complex flow physics, geometry, and interactions. An example is the measurement of a turbulent boundary layer over a flat plate. The experiment data set contains detailed data collected with high accuracy. The boundary conditions and initial conditions are accurately measured.
Benchmark Cases involve fairly simple hardware representing a key feature of the system.
The flow field contains only two separate flow features of the flow physics which are likely coupled. Subsystem Cases involve geometry of a component of the complete system which may have been simplified. An example is a test of a subsonic diffuser for a supersonic inlet. The exact inflow conditions may not be matched. The quality and quantity of the experiment data set may not be as extensive as the benchmark cases.