Preflight Boundary-Layer Stability Analysis of BOLT Geometry

Boundary-layer stability and laminar-to-turbulent transition are examined on the Boundary Layer Transition flight-test vehicle using predicted flow conditions at ascent and descent flight times. The parabolized stability equations technique is used predominantly for this analysis because it has proven to be efficient and accurate in modeling the transition process on other three-dimensional geometries. The various potential transition mechanisms are identified in the region outboard of the centerline to the leading edge, and their linear amplification is discussed. These mechanisms include second-mode and crossflow instabilities. Stationary crossflow is predicted to be the dominant mechanism for breakdown away from the centerline and leading edge, and nonlinear analysis is performed. The nonlinear parabolized stability equations are used for this analysis, and comparisons with a direct numerical simulation are performed. Partially through this verification, a physics-based technique to model the heating rates of nonlinearly developing stationary crossflow is assessed.