Allowable Trajectory Variations for Space Shuttle Orbiter Entry-Aeroheating CFD

摘要

Reynolds-number criteria are developed for acceptable variations in Space Shuttle Or-biter entry trajectories for use in computational aeroheating analyses. The criteria deter-mine if an existing computational fluid dynamics solution for a particular trajectory can be extrapolated to a different trajectory. The criteria development considers twelve types of computational aeroheating data, such as boundary layer thickness. For each type of da-tum, the allowable uncertainty contribution due to trajectory variation has been set by the Entry Aeroheating Subsystem team. Then Reynolds-number relations between trajectory variation and output uncertainty are determined. From these relations the criteria are es-tablished for the maximum allowable trajectory variations. The most restrictive criterion allows a 25% variation in Reynolds number at constant Mach number between trajectories.