Some Recent Innovations in Wind Tunnel Testing Techniques 690677

In recent years, several innovations have been made in wind tunnel testing techniques which have significantly improved the testing cost effectiveness. Use of colored water spray in low speed testing causes unsuspected vortices to stand out allowing quick and accurate drag reduction filleting to be prepared. Simultaneous force and pressure model transonic testing has reduced the time and cost to arrive at a low drag airplane configuration by more than 50%. Means are being developed to accurately predict high Reynolds number transonic airloads from low Reynolds number data. The use of accurately sized glass beads to provide boundary layer transition for transonic testing has been found to reduce run-to-run drag data scatter by more than 50%.