Active reduction of skin friction drag using low-speed streak control

Abstract

The objective of this study is to determine the effectiveness of using an active sensor/suction technique to identify and remove low-speed streaks from a turbulent boundary layer in order to reduce skin friction. An experimental investigation was conducted in both water and wind tunnel facilities to visualize low-speed streak development and their active removal. Quantitative drag reduction measurements of an active sensor/suction system were also obtained. Flush mount hot-film sensors were used with a detection algorithm to identify low-speed streaks and activate suction ports to remove the streaks in their growth phase. Due to the small streak areas and high burst frequencies involved, a MEMS based micro-valve was investigated for the active suction port. Results from this study show that turbulent skin friction reductions are possible using low suction rates and reduced mass flows. In addition to the experimental results, parameter sensitivity and sizing studies were also performed in order to determine the suitability of an actual active sensor/suction system. As Cs Qs Re t TB Vw