In order to achieve an aerodynamic body design, it is still necessary to undertake experimental tests in a wind tunnel despite the availability of computer-aided computational methods.
Based on the principle of guidance of air, one can distinguish between two designs of wind tunnels, the Eiffel- and the Göttinger design. A wind tunnel in the Eiffel design (see next slide) is open to the intake as well as to exit side, while the Göttinger design (slide 43) consists of a closed air circuit.