Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A Wind tunnel is a research tool used in aerodynamic research. IT is used to study the effects of air moving past solid objects.WInd tunnels were first proposed as a means of studying vehicles (primarily airplanes) in free flight. THe wind tunnel was envisioned as a means of reversing the usual paradigm: instead of the air''s standing still and the aircraft moving at speed through it, the same effect would be obtained if the aircraft stood still and the air moved at speed past it. IN that way a stationary observer could study the aircraft in action, and could measure the aerodynamic forces being imposed on the aircraft.