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A system for evaluating the near-field pressure distribution around a supersonic flight model by combining experimental and numerical diagnostics has been developed. Experimental measurement is conducted using a ballistic range with four kinds of axi-symmetric flight models. Schlieren flow visualization is recorded using a high-speed framing camera and near-field pressure histories are measured using piezoelectric pressure transducers flush-mounted on the surface of flat plates in the test section. The numerical diagnostics is done using FaSTAR, a numerical simulation tool developed by the Japan Aerospace Exploration Agency (JAXA). The experimental and numerical data are compared to each other, and the numerical results well validated. Based on the numerical results, it becomes possible to estimate the accuracy of experimental conditions including the flight path and angle of attack, which cannot readily be determined only from experimental data, and to discuss the relationship between peak overpressure and aerodynamic performance. Satisfactory agreement between the experimental and numerical results at a flight Mach number of 1.66 ± 0.02 and important insights related to rear boom strength are obtained.

:To examine the possibility of sonic boom mitigation by the supersonic biplane with a fuselage, two kinds of wing-fuselage models for the ballistic range experiment were designed by using CFD simulations. One was the low-boom model with a blunt nose and the other was the high-boom model with a spike nose. From the CFD result, the near-field pressure strength from the low-boom model becomes 70% of that of the high-boom model. The far-field pressure peak of the low-boom model becomes 85% of that of the high-boom model. To verify the near-field pressure signature calculated by CFD, the experimental model using the supersonic biplane with a finite-thickness leading edge was designed and launched with the ballistic range. As a result, the reliability of the CFD result was confirmed.

The effectiveness of a "staged aftbody" proposed by Toyoda et al. (AIAA J., Vol. 52, 2014, pp. 2899-2901 was further investigated using an aeroballistic range with a free-flight Mach number of 1.7. Near-field pressure signatures were obtained from a pressure transducer that was flush-mounted on a flat plate. From these signatures, far-field pressure signatures were obtained by the waveform parameter method. It was demonstrated that a flight model whose length-todiameter ratio was even as high as 21 exhibited considerable elongation of the overall tail-boom pressure signature duration, thereby effectively mitigating the tail boom.

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