Experimental Investigation of the Downstream Effects from High-Speed Fluid Structure Interactions and the Development of Supporting Diagnostics

This work investigates how surface deformations impact the downstream flow field and the development of diagnostic techniques to improve future experimental efforts. Three configurations using the UTSI Mach 2, Mach 4, and Mach 7 facilities are investigated with the primary diagnostics being schlieren, diagnostic paint, and focused laser differential interferometry (FLDI) along with other supporting diagnostics. The goals of these experiments were to identify the primary mechanism of these effects and to quantify the potential impact these effects would have on a canonical control surface. Experiments in the UTSI Mach 4 showed that unless separation occurred, the downstream turbulent boundary layer was left unaffected by the presence of a surface deformation. Instead, weak shockwaves emanating from the deformation were identified as the most significant downstream effects. The designation of these shockwaves as weak came from the lack of changes in flow conditions after these waves, indicating that their impacts were localized to the waves themselves. These localized effects were highlighted in experiments conducted in the UTSI Mach 7 facility where the deformation shockwaves were impinged onto a downstream flare, resulting in increased surface heating at the impingement locations. Due to the complexity of the models and flow fields, large scale, a series of improvements to laser-based diagnostics have been made to increase the capabilities of future researchers in this area of study. These improvements center around the deployment of non-intrusive velocimetry to a test and evaluation (T\&E) facility, and the improvement of FLDI by changing the lens configuration from spherical to cylindrical and quantifying the efficacy of using a high-speed camera as a detector. Using the UTSI Mach 2 and Mach 2.3 wind tunnels, the efficacy of using a high-speed camera as a detector was characterized, highlighting the trade-offs between lower sample rates and increased sensor size. When combined with cylindrical lenses, the high-speed camera added a unique capability to the current state-of-the-art in FLDI measurements by achieving a highly resolved measurement over a thin-turbulent boundary layer.