The development of wind tunnels accompanied the development of the airplane, with large tunnels built during World War II and supersonic tunnels constructed as supersonic aircraft were developed. Wind tunnel testing was considered strategically important during the Cold War for aircraft and missile development. Advances in computational fluid dynamics (CFD) have reduced the demand for wind tunnel testing, but have not completely eliminated it.
English mathematician Isaac Newton displayed a forerunner to the modern wind tunnel in his book Philosophiæ Naturalis Principia Mathematica. English military engineer Benjamin Robins invented a whirling arm apparatus to determine drag, performing some of the first experiments in aerodynamics. Sir George Cayley also used a whirling arm to measure the drag and lift of airfoils. Otto Lilienthal used a rotating arm to make measurements on wing airfoils, establishing their lift-to-drag ratio polar diagrams.
Francis Herbert Wenham addressed the drawbacks of whirling arm tests by inventing the first enclosed wind tunnel in 1871. Wenham and John Browning made fundamental discoveries, including the measurement of l/d ratios and the beneficial effects of a high aspect ratio. Konstantin Tsiolkovsky built an open-section wind tunnel with a centrifugal blower in 1897, determining the drag coefficients of flat plates, cylinders, and spheres. Osborne Reynolds demonstrated that airflow patterns on a scale model would be the same for a full-scale vehicle if a certain flow parameter, now known as the Reynolds number, were the same in both cases.
The Wright brothers used a simple wind tunnel in 1901 to study airflow over various shapes while developing the Wright Flyer. In France, Gustave Eiffel built his first open-return wind tunnel in 1909, powered by a 67 hp electric motor. Eiffel ran about 4,000 tests in his wind tunnel between 1909 and 1912, setting new standards for aeronautical research. His laboratory was later moved to Auteuil, where his 7-foot test section tunnel is still operational today.
While initially developed for aeronautical research, the principles of wind tunnel testing were later applied to automotive engineering. Wunibald Kamm built the first full-scale wind tunnel for motor vehicles. Wind tunnel testing of automobiles began in the 1920s, on cars such as the Rumpler Tropfenwagen, and the Chrysler Airflow. Initially, scale models were tested, then larger wind tunnels were built to test full-scale cars with the capability to measure aerodynamic drag which enables improvements to be made for reducing fuel consumption.