Near-Field Pressure Signature Measurements of NASA X-59 in JAXA 1 m × 1 m Supersonic Wind Tunnel

Abstract

This paper describes the near-field pressure signature measurements of a 1.62%-scale model of the NASA X-59 flight demonstrator in the JAXA 1 m × 1 m supersonic wind tunnel (JSWT) conducted jointly by NASA, Boeing, and JAXA. The aim of this test was to cross-validate the near-field pressure signatures between facilities and provide data for a workshop to be conducted by the three parties. At the JSWT, a shark-fin type pressure rail originally designed by JAXA is used for the near-field pressure signature measurement to enable easier comparison between experimental near-field pressure signatures and those obtained via numerical analysis without complex rail correction. With the data obtained through this test, the uncertainty of the near-field pressure signature measurement, repeatability, and characteristics of the proposed rail were investigated. It was found that the obtained signatures were sufficiently accurate to clearly show the differences between the X-59 configurations. Comparison with numerical analysis revealed good agreement except for the most downstream portion of the signature. Based on the numerical analysis and schlieren images, it was inferred that the difference was caused by testing at lower Mach numbers rather than the rail design point resulting in a relatively greater effect on rail interference. Additionally, the difference between numerical analysis and wind tunnel testing in the shock wave pattern generated in the plume area of the X-59 model was indicated. The proposed pressure measurement method can be performed in a relatively small wind tunnel and is useful for the design validation of low-boom aircraft and for comparison with numerical analysis.