Wind Tunnel Corrections
For the aerodynamic development of a vehicle, it must be noted that the flow situation around a vehicle in a wind tunnel does not exactly correspond to the flow situation on the road due to blocking effects and, therefore, results in faulty measurement results. These blocking effects can be traced to various boundary conditions in the wind tunnel, whereby a differentiation must be made between different test section forms . In closed test sections, the forces measured are generally too large; in open test sections, they are too small.
Research activities have been undertaken as early as around 1920 to improve our understanding of these blocking effects and to develop mathematical correction methods. An improved understanding of these effects would make it possible on one hand to avoid them when building new wind tunnels. On the other hand, a better comparability between different tunnels could be achieved with a general mathematical correction method. Furthermore, blocking effects could be tolerated when building a wind tunnel in order to lower the construction costs. Measuring errors could then be corrected mathematically.
For wind tunnels with a closed test section, approved correction methods have been in place for some time that are used as a standard in many tunnels. The development of correction methods for wind tunnels with open test section has, however, proven to be incomparably more difficult. The development of such methods is part of the ongoing research efforts at the FKFS.
© 2011 FKFS – Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren Stuttgart | Impressum | Datenschutz