Instability Free Three-Dimensional Hypersonic Laminar Boundary Layer Steady-States for Linear and Nonlinear Stability Analyses
Abstract
Stationary instabilities are a common feature of three-dimensional boundary-layers, which are typically found in swept wings, axisymmetric cones at an angle of attack and elliptic cones. When these geometries are clean, i.e. without discrete surface roughness, traditional computational fluid dynamics codes have severe difficulties making sure they are not excited by numerical errors and appear in the steady-state. When these modes are excited in a physically meaningful way, such as in the presence of discrete surface roughness, this task becomes nearly impossible. Hence, steady-states contaminated by either numerically or physically induced stationary modes are often used in linear stability analysis.This means any stability analysis using such steady-states is in fact uncovering secondary instability mechanisms associated with stationary modes, and not the primary mechanisms that lead to their formation. The objective of this proposal is to generate instability free steady-states for circular and elliptical cone hypersonic laminar boundary-layers using state-of-the-art numerical techniques recently developed by the principal investigator. They are able to damp stationary modes through special time integrations schemes, which do not aaffect the resulting steady-state spatial resolution. These steady-states are then going to be analyzed using existing stability codes developed by collaborators of the principal investigator. In doing so, the origins of stationary crossflow vortices should be clarified.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 19, 2018
- Source ID
- FA95501810419
Entities
People
- Leonardo Alves
Organizations
- Air Force Office of Scientific Research
- Fluminense Federal University
- United States Air Force