Detailed Uncertainty Analysis of the Ares I A106 Liftoff/Transition Database

摘要

The Ares IA106 Liftoff/Transition Force and Moment Aerodynamics Database modeled the aerodynamics of the Ares I crew launch vehicle from the moment of liftoff through the transition from high to low total angles of attack and included the effects of the launch tower on the vehicle aerodynamics. The database was developed from wind-tunnel data acquired in NASA Langley Research Center's 14- by 22-Foot Subsonic Wind Tunnel using a 1.75 % scale ., model of the vehicle and tower assembly. The uncertainty model contained contributions from three primary sources: experimental uncertainty, database modeling uncertainty, and database query interpolation uncertainty. The uncertainty for each source was quantified using the available data, and the total uncertainty was a root-sum-square combination of the three sources. The most significant uncertainty source was experimental uncertainty. The database and uncertainty model yielded significant improvements in the fidelity of the aerodynamic predictions for this flight regime over previous estimates based on limited computational and empirical data for the Ares I-X flight test vehicle. In addition, the maximum aerodynamic force in a dispersed case pushing the vehicle toward the launch tower assembly was 40% lower than the worst-case estimate from the previous data.