Multi mode Induced Transition in Hypersonic Boundary Layers
Abstract
The compact size and higher aerodynamic heating loads associated with hypersonic vehicles make it more difficult to maintain their structure and internal components below their upper temperature limits. These vehicles may also tend to bend-warp because of induced thermal gradients across their thin structures. Also challenging is the potential for ablation, erosion, and oxidation of sharp airfoil leading edges [29]. Aerodynamic heating is driven by alternations of the mean boundary layer velocity by interactions of the multiple instability modes present in hypersonic boundary layer during transition. Although most hypersonic transition studies focus on the growth and breakdown of one type of instability mechanism, it is more likely that the interaction of different hydrodynamic instabilities mechanisms (e.g. modes) are responsible for the breakdown of the laminar flow and the onset of transition. The among the novel aspects of this project are that is approaches multimode transition by: a) Using a nonsimilar hypersonic boundary layer flow as the meanflow; b) Calculating the interaction among first, second and Gortler modes present in hypersonic boundary layers (e.g. second mode and Gortler modes-first mode; and self interactions of first modes) to determine their impact on transition; c) Calculating the resulting mean flow distortion (MFD) to determine the impact of multimode transition on surface heating loads; and d) Using wind tunnel data from a quiet tunnel to validate the computational results. The proposed study outlined above contains a balanced combination of experiments, computations and theoretical efforts. The parabolic stability equations (PSE) provide an economical means for studying the evolution of wavelike disturbances in boundary layers. The governing equations for these flows are generally elliptic in character so that the value of any flow variable at each point in the domain depends on its values at all other locations in the domain.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910406
Entities
People
- Sonya T. Smith
Organizations
- Air Force Office of Scientific Research
- Howard University
- United States Air Force