Date of Award
2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Mechanical and Aerospace Engineering
Committee Chair
Phillip Ligrani
Committee Member
Haiyang Hu
Committee Member
Jason Cassibry
Committee Member
Hallie Collopy
Committee Member
George Nelson
Research Advisor
Phillip Ligrani
Subject(s)
Unsteady flow (Aerodynamics), Schock waves--Analysis
Abstract
This dissertation considers interactive relationships between a normal shock wave and the downstream shock wave leg of the associated lambda foot, as well as between a normal shock wave, time-varying static pressure, surface temperature fluctuations, and surface heat flux variations as measured along the bottom surface of the test section. Such relationships are investigated as they vary with two different magnitudes of inlet unsteady Mach wave intensity and are characterized using shadowgraph flow visualization data, as well as power spectral density, magnitude squared coherence, and time lag data. Employed for the investigation is a specialty test section with an inlet Mach number of 1.54, as utilized within a transonic/supersonic wind tunnel. Considered are both high and low inlet Mach wave intensity distributions at the test section entrance, denoted HMWI and LMWI. The most significant sources of flow unsteadiness within the present investigation are mostly associated with the normal and oblique shock waves (with LMWI), and mostly with inlet flow disturbances from unsteady Mach waves (with HMWI). The present experimental results additionally evidence important connections between the normal shock wave and unsteady flow events within lower portions of the lambda foot, especially near the adjacent boundary layer separation region. Additionally, this study considers the interactions of the time-varying length of the separation zone below the normal shock wave boundary layer interaction relative to other parts of the flow and the surface static pressure variation. Overall data trends indicate that separation length flow events at different frequencies are generally more strongly correlated with unsteady surface static pressure and with the instantaneous tracked normal shock wave location with HMWI, relative to the LMWI arrangement. In addition, with HMWI, results for the lowest frequencies considered indicate that unsteady flow events propagate from the separation zone to the normal shock wave and then to the Kulite sensor below the normal shock wave. In contrast, with LMWI, results for the lowest frequencies indicate that unsteady flow events propagate from the normal shock wave to the Kulite sensor below the normal shock wave and then to the separation zone.
Recommended Citation
Manneschmidt, Ward, "Correlated unsteady interactions between a normal shock wave, lambda foot, and other flow events" (2025). Dissertations. 462.
https://louis.uah.edu/uah-dissertations/462