• Dr. Lian Duan
  • National Institute of Aerospace
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Heng Xiao

Improved energy efficiency is a high priority area for future aircraft vehicles. Prior studies have shown that reduction in drag can have a major impact on fuel burn. The general strategies for skin-friction drag reduction include laminar flow control to delay laminar-to-turbulent transition and turbulent flow control to reduce turbulent drag. In this talk, we first describe our general effort in laminar flow control and turbulent drag reduction. Then, we focus on turbulent drag reduction by riblets (biomimetically inspired micro-grooves), which have long been recognized as a premier approach for reducing skin-friction drag. Although their effectiveness in reducing drag has been extensively demonstrated in the subsonic regime, few studies have been conducted in the supersonic regime and none for hypersonic flows. Moreover, the detailed drag reduction mechanism has not been well understood, partly because of the difficulties in making measurements in the close vicinity of the grooves. High-fidelity simulations are used to assess the effectiveness of riblets in reducing drag at high speeds and elucidate the drag-reducing mechanism.