Aircraft concepts are always driven by the requirements of the desired
m- sion. A di?erent purpose for the use of the aircraft consequently
results in a di?erent design. Therefore, depending on the intended
outcome, con?i- ing requirements need to be ful?lled, for example,
e?cient cruise speed and greatercargocapabilities, in combinationwith
shorttake-o?andlanding ?eld lengths, or high speed and agility combined
with variable payload demands. Due to the highly complex, non-linear
physical environment in which aircraft operate, this task demands that
the most advanced methods and tools are employed, to gain the necessary
understanding of ?ow phenomena, and to exploit the ?ow physics to
achieve maximum aircraft e?ciency. Inthe naturalsciences, researcherstry
to create andextend humankno- edge by understanding and explaining the
mechanisms of physical processes. In engineering, a designer is limited
by certain requirements, and in order to ful?l these requirements the
necessary technical tools need to be designed. In general, for a given
problem the corresponding scienti?c or technical solution is sought. In
order to successfully advance from a problem towards a solution, three
main methods may be used. The two classical methods include theory and
experiment, which are now being complemented by a third method, -
scribedasnumericalsimulation.Theexperimentalapproachis basedonph- ical
observation, measurement of relevant values, and methodical variation of
the subject matter. For example, such experiments are used to gain a ph-
ical understanding as well as to validate and investigate design
alternative