Scaling: Wind tunnel to flight

Wind tunnels have wide-rangiug functionality, including many applicitions beyond aeronautics, and historically have been the major source of information for tech. nological aerodynamics/aeronautical applications. There are a myriad of scaling issues/differences from flight to wind tunnel, and their study and impacts are uneven and a function of the particular type of extant flow phenomena. Typically, the most serious discrepancies are associated with flow separation The tremendous on. going increases in numerical siumlation capability are changing and in many aspects have changed the function of the wind tunnel from a (scaled) "predictor" to a source of computational calibration/validation imformation with the computation then utilized as the flight prediction/scaling tool. Numerical simulations call increasingly include the influences of the various scaling issues. This wind tunnel role change has been occurring for decades as computational capability improves in all aspects. Additional issues driving this trend are the increasing cost (and time) disparity between physical experiments and computations, and increasingly stringent accuracy requirements.