Comparisons of Surface Roughness in Laminar and Turbulent Environments for Orion Thermal Protection System

This paper addresses surface roughness measurements obtained from arc jet tests of Avcoat that were conducted in four different facilities at NASA Ames Research Center for Orion. Approaches and techniques for testing, measuring, and modeling fluid and material response in laminar and turbulent flows in these facilities are presented. Measured test conditions are consistent with corresponding computational simulations in each facility, and test results demonstrate that while the laminar test facilities create flow artifacts on the surfaces of the test samples, the turbulent test facility generates material roughness without the presence of flow patterns.