ABSTRACT
In many areas, information of fundamental nature can be derived from the experiments, which is otherwise not possible or cumbersome from the computations. Experiments to investigate aerodynamic problems can be carried out in various approaches, including flight testing, missile launches, drop test water tunnels, ballistic ranges, and wind tunnel investigations. Despite significant developments in the field of computational fluid dynamics, wind tunnel testing results remain critical for guiding specific design judgments for various engineering problems. A closed-circuit wind tunnel, on the other hand, is a tunnel where the same fluid recirculates through the test section in a specified path. In low-speed wind tunnels, air is the common working fluid. The fluid compressibility significantly impacts tunnel design; the test section has the smallest area in a subsonic tunnel, whereas the throat has the smallest area in a supersonic wind tunnel. A wind tunnel calibration entails calculating the mean values and homogeneity of different flow parameters in the test section.
