Linear Modal and Non-Modal Instability Analyses of High-Speed Laminar Separated Flow Over Complex Geometries. Part 1: Algorithmic Developments
Abstract
On the theoretical front, necessary algorithmic developments to address BiGlobal axisymmetric modal and nonmodal instability of supersonic and TriGlobal modal instability of hypersonic flow have been undertaken and first analysis results have been obtained. Work in the completed phase comprised derivation of the direct compressible axisymmetric BiGlobal Linearized Navier-Stokes Equations (LNSE) and the corresponding fully three-dimensional (TriGlobal) LNSE in generalized coordinates, using two alternative but equivalent theoretical approaches employing the transformation Jacobians and the chain rule or metric factors and Christoffel symbols. The corresponding equations have been implemented into the matrix-forming Linear Global analysis for Hypersonic Transition (LiGHT) massively parallel eigenvalue and singular value problem solver. Work in this phase also included computation of steady laminar supersonic axisymmetric base flows on the HCF geometry, as well as fully three-dimensional hypersonic flow over the Oberkampf body, followed by first linear global stability analyses in both conxC;figurations. In the HCF geometry modal and nonmodal analyses have been performed, respectively by solving the eigenvalue and singular value problem on generalized coordinates, while on the Oberkampf body the residuals algorithm was employed to extract the least damped global mode. In both geometries, the intimate connection of instability in the laminar separation zone and that of synchronized oscillations in the shock layer has been documented for the xC;first time. Results have been presented in the 2020 AFOSR Annual Review, the 2020 APS and 2021 AIAA SciTech conferences, as well as the Spring and Autumn meetings of the NATO STO AVT-346 Hypersonic Transition group and published as AIAA conference papers, while preparation of archival journal publications is underway.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 2021
- Accession Number
- AD1161241
Entities
People
- Vassilios Theofilis