SPECTRAL ENERGIES LLC — Department of Defense SBIR Phase I: N202-141

Description

In this Phase I effort, we propose to analyze, computationally design, and characterize in a quiet hypersonic wind tunnel, flight-representative roughness patterns for hypersonic transition control on lift-generating geometries. First, we will select and design baseline roughness/wavy elements in consultation with flight-experienced hypersonic engineers, including at JHU/APL, sampling and characterizing impressions taken from flight geometries. Next, we will use high-fidelity numerical analyses based on full Navier-Stokes equations in conjunction with stability theory to select and design patterned discrete roughness to control the growth of stationary crossflow vortices and delay the laminar-turbulent transition.  Finally, we will develop surface patterns/roughness elements, both flight-representative and suitably optimized, for integration with a hypersonic wind tunnel model based upon the well-characterized HIFiRE-5 geometry, fabricate the representative and optimized roughness arrays using Direct Contactless Microfabrication technology, and plan/execute hypersonic wind tunnel tests with low freestream disturbances using state-of-the art optical diagnostic and surface measurements. These results will inform refined models to define and design effective and practical discrete roughness patterns for the suppression of turbulent transition and therefore enhanced, more predictable aerodynamic performance, which is particularly critical for improved boost-glide weapon configurations, especially for Naval applications where volume, mass, and range are at a premium.