The Design of Wind Tunnels: Notes on Past History and Present Tendencies, Showing the Advantages of the Open‐Jet type

DURING the last year or two the construction of several new wind tunnels in this Country has been commenced, after many years of inactivity in this direction. The new tunnels are intended either to bring existing equipment up‐to‐date or to meet specific needs for researches which cannot be satisfactorily carried out in the older tunnels. In all cases the new tunnels are of types very different from those previously in use in this country, and it is interesting to trace the reasons for the change. In order to do this it would be well to review the history of the development of the existing tunnel equipment, in order to understand in the first place why the standard type of wind tunnel used in this country was entirely different from, and in some respects less efficient than, that developed on the Continent. When the study of aerodynamic problems was undertaken at the National Physical Laboratory in 1909, the question of a suitable design of wind tunnel was naturally one of the first to be raised.