Aerodynamic Noise Tests on X-20 Scale Models. Volume II. Summary and Analysis Report

摘要

Summaries of fluctuating pressure data presented in Volume I for 1/15th-scale X-20 models are made and discussed. Particular emphasis is given to the high over-all rms pressures measured aft of convex corners during transonic test conditions. Additional information relating to these pressures is presented in the form of pressure histories, peak-amplitude distributions, and power spectral densities. Fluctuating-pressure data and space correlation measurements for three closely spaced microphones are presented, illustrating the local nature of the high-level pressures. Analyses of trends for the maximum over-all rms pressure levels for the X-20 tests and other wind-tunnel tests are made. Design charts are developed for predicting maximum levels aft of cone-cylinder transition sections as functions of transition angle and distance downstream of the transition shoulder. Recommendations are made regarding future aerodynamic noise experimental programs. (Author)