Analysis of Unsteady Flow Phenomena on a Generic Multi-Delta-Wing Configuration at Transonic Speeds based on Fast-Response Pressure-Sensitive Paint

Abstract

The following thesis deals with the evaluation of Fast-response pressure sensitive paint (iPSP) data that has been acquired for the DLR-F23 configuration at the Transonic Wind Tunnel Göttingen (DNW-TWG). The respective triple-delta-wing configuration has been examined considering a Mach number between 0.55 and 1.15 and an angle of attack between 9° and 24°. Due to the wing topology vortex systems, namely inboard vortex (IBV), midboard vortex (MBV), and outboard vortex (OBV), develop in dependence of the Mach number and the angle of attack. The thesis aims to identify and describe the resulting unsteady phenomena, such as vortex breakdown, vortex-vortex interaction, and vortex-shock interaction. Therefore, the physical mechanisms of delta-wing configuration flows, as well as the developing vortex topology, especially focusing on the triple-delta wing, and the iPSP measurement technique are being introduced. An evaluation toolchain, based on the visualization of the mean pressure values and pressure fluctuations, concludes the most relevant pairs of Mach number and angle of attack, which is subsequently analyzed through the utilization of diverse decomposition algorithms, such as Proper orthogonal decomposition (POD) and Dynamic mode decomposition (DMD). The results are separated into the subsonic, transonic, and supersonic flow cases and elaborated with special regard to the occurring flow phenomena. Furthermore, the influence of the experimental parameters, Mach number and angle of attack, on the obtainable shock and vortex breakdown positions is presented. The concluding discussion deals with the advantages and disadvantages of the applied measurement technique and the applicability of the postprocessing algorithms to the iPSP data.