An experimental exploration of supersonic vortex mechanics in oblique shock-vortex interactions

This thesis is exploratory in nature, but its goals have specific intentions.Often with complex compressible flow phenomena, the respective literature lacks a reliable bridge connecting qualitative experimental campaigns and numerical simulations. Specifically with Oblique Shock-Vortex Interactions (OSVI), many simulations’ of the flow employ models that are approximated on assumptions that have yet to be totally validated by experiment, especially via non-intrusive experimental methods. In these cases, the confirmation of numerical accuracy is attempted only by comparisons to qualitative visualizations of the phenomenon, such as shadowgraph or schlieren imaging. This study is a potential kickstart to a body of work that aims tobridge the gap between qualitative experiments and numerical simulations. Having quantitative experimental data obtained via non-intrusive methods is paramount to confirming the findings of numerical works. In a broader scope, understanding the effects of OSVI has potentially vast implications for high-speed jet and missile designers that may experience the detrimental consequences of such an interaction during supersonic flight. Through the use of Stereoscopic Particle Image Velocimetry (SPIV),an in-depth test matrix is carried out. This matrix consists of multiple supersonic wind tunnel setups producing OSVI’s of varying strengths. The campaign was designed in such a way so as to test the effects ofvortex strength and shock strength on the overall interaction. This work is concerned with the impingement of wing-tip generated vortices, produced by an upstream diamond fin, with downstream wedge-shocks. Using the Mach 3.4 Rutgers University Emil Buehler Supersonic Wind Tunnel, SPIV trials were performed. The results include varying types of flow vector colormaps that show the characteristics of the flows in question. These flows include the cross-section of wing-tip vortices, planar oblique shocks, the 2D OSVI, and the 3D OSVI—the latter of which is compiled volumetrically. Due to particle entrainment issues within the high-shear regionsof the vortex cores, there is a fair degree of quantitative uncertainty. Nonetheless, the results indicate that, with the present experimental setup, a significant altering of the shock-downstream velocity is seen during OSVI. This alteration seems to become increasingly dramatic with both increasing vortex strength and shock strength. Whether or not vortex breakdown occurred in the trials is not readily obvious from the 2D visualizations. However, it became clear from the 3D interaction that the vortical structure survives shock interaction and is turned parallel to the downstream wedge.M.S.Includes bibliographical reference