Geometry-Independent Hypersonic BoundaryLayer Transition Prediction

One of the fundamental challenges of fielding and maneuvering a hypersonic vehicle is predicting the large changes in heat transfer and aerodynamic performance associated with the transition of the surface boundary-layer flow from laminar to turbulent during flight. Legacy methods for analyzing boundary-layer transition are overly simplistic and do not account for the intricate flow patterns of modern vehicles with complex three-dimensional shapes. This article introduces work utilizing a novel methodology, known as input/output (I/O) analysis, recently applied to hypersonic flows. This methodology is completely free of geometric constraints and has significant potential to answer many of the open questions in transition analysis. The article presents examples of I/O analysis applied to hypersonic flow over a 7° half-angle sharp cone and to the Boundary Layer Transition (BOLT) flight experiment. The analysis uses computational tools that were built in collaboration with the University of Minnesota and VirtusAero as part of a Johns Hopkins University Applied Physics Laboratory (APL) independent research and development project.