Title: Experiments in Fluids - Master Lecture Series (Ⅱ) In-Flight Transition and its Control
Time: 15:00 to 16:00, Thursday, April.11, 2024
Place: Zhenhua Conference Hall, School of Mechanical Engineering
Host: PENG Di, Professor (Institute of Turbomachinery)

Biography
Cameron Tropea graduated from the University of Toronto in Engineering Sciences, followed by a Masters degree in Mechanical Engineering (1977). He completed his Dr.-Ing. in Civil Engineering at the Technical University of Karlsruhe (1982) and his Habilitation in Fluid Mechanics at the University of Erlangen-Nürnberg (1991) where he was appointed as Professor of Fluid Mechanics until 1997. This was followed by an appointment as head of the Institute of Fluid Mechanics and Aerodynamics at the Technische Universität Darmstadt.

Abstract
In an effort to determine the influence of atmospheric turbulence on the transition of natural laminar flow (NLF) airfoils, such as those found on gliders, one of the first steps is to characterize the turbulence of the lower atmospheric boundary layer. For this purpose, measurements were performed using a motorized glider (Grob 109b), outfitted with an instrumented wing glove. The possibility of duplicating the measured turbulence spectra in a wind tunnel were also investigated by a project partner at the University of Stuttgart, and comparisons will be drawn between the two situations. The extent to which the en method can be modified to predict transition is explored. This was followed by a study in which the laminar-turbulent transition was delayed on the pressure side of the wing using two methods. The first was to add momentum to the boundary layer, modifying the neutral curve of linear stability theory. The second used active wave cancellation with dielectric barrier discharge (DBD) plasma actuators to suppress Tollmien-Schlichting waves. Both methods were tested in the wind tunnel and the latter was demonstrated in-flight.