Transition to turbulence in high-speed flight- Incoming disturbances and particulates
Abstract
At high speeds, flight vehicles experience extreme aero-thermal loads when the flow transitions from a laminar to a turbulent state, either due to incoming disturbances or particles. Free-stream disturbances can modify and be modified by the leading-edge shock of the flight vehicle; Downstream, the boundary layer is only receptive to the a portion of the disturbance spectrum, and the impact of the flow stability depends on the amount of energy contained in these modes. Provided sufficient energy is present in the unstable frequency band, the boundary layer can be destabilized and break down to turbulence. Particles, on the other hand, are imparted with a sudden acceleration as they traverse the leading-edge shock of the flight article, and their trajectories are deflected as they approach the flight article. If the particles are sufficiently small, they respond to the flow between the shock and the vehicle and behave as tracers that avoid impact with the surface. The larger particles will enter the boundary layer, potentially impact the surface, and generate wave packets that spread as they propagate downstream. Existing efforts are aimed at characterizing the flight environment, both in terms of measuring the disturbance fields and particulates, followed by evaluating the potential impact of such disturbances. This effort adopts an alternative view.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 29, 2024
- Source ID
- FA95502310280
Entities
People
- Tamer A. Zaki
Organizations
- Air Force Office of Scientific Research
- Johns Hopkins University
- United States Air Force