Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet Flows with Shock Interactions

摘要

NASA and the U.S. aerospace industry are performing studies of supersonic aircraft concepts with low sonic boom pressure signatures. The computational analyses of modern aircraft designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty remains in the aft signatures due to boundary layer and nozzle exhaust jet effects. Computational solutions of flight vehicles are difficult to assess since experimental sonic boom data are without inlet and nozzle exhaust jet effects, and obtained at significantly lower Reynolds numbers. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel is planned for February 2016 to address the nozzle jet effects on sonic boom. The experiment will provide pressure signatures of test articles, designed to encompass a variety of waveforms from aft aircraft components, after passing through cold nozzle jet plumes. The test will provide a variety of nozzle plume and shock interaction data for comparison with computational analyses. A large number of high-fidelity numerical simulations of a variety of shock generators were evaluated to define a reduced collection of five suitable test models. The computational results of the candidate wind tunnel test models as they evolved are summarized, and pretest computations of the final designs are provided.