Measurement and Assessment of Flow Quality in Wind Tunnels

With increased commercial competition, great pressure is being applied to effect aerodynamic design changes that will improve fuel economy and performance. But, for example, as we are now concerned with small changes in drag count, potential sources of improvement are much more likely to be masked by poor flow quality. We may have reached the stage where the lack of suitable facility flow quality will hinder and dictate the rate of progress of ground based testing. Few measurements have been made in the Nation's wind tunnels, and in those cases, large discrepancies have been found between full-scale and predicted performance. Consequently, there is an urgent need for in-situ measurements to measure flow quality and the performance of turbulence and noise suppression devices. To meet these challenges, a unique research program is proposed to clarify and alleviate the aerodynamic problems associated with adverse wind tunnel flow quality. It combines innovative advances in data base assessment and management, and new approaches to turbulence instrumentation and analysis. Standardized turbulence measurement techniques and data analysis procedures will be established and used to document the flow quality in our major test facilities.