Sonic‐boom research activities in the Japan Aerospace Exploration Agency (JAXA)

Abstract

Some sonic‐boom research activities conducted in the Japan Aerospace Exploration Agency (JAXA) are summarized. JAXA started a scaled supersonic experimental airplane program named NEXST‐1 in 1996 in order to establish advanced CFD‐based design technologies. The flight test of the NEXST‐1 was conducted in October, 2005 at Woomera test range in Australia. The sonic‐boom signatures of the NEXST‐1 were measured on the ground in order to confirm the possibility of demostrating the low sonic‐boom design technology with scaled experimental airplanes for a future low‐boom demonstrator program. The measured sonic‐boom signatures were compared to the signatures extrapolated from the near‐field pressure signatures predicted by CFD and panel method or measured in the supersonic wind tunnel. Low‐sonic‐boom design technology using gradient‐based optimization tool with CFD is developed and applied to a non‐axisymmetrical fuselage design concept in order to reduce the drag penalty. JAXA works on a human acceptability study in cooperation with Kawasaki Heavy Industries (KHI) using their sonic‐boom simulator. Some low‐boom signatures in addition to some typical N‐shaped signatures with various peak pressure levels were simulated in the boom box and used for subjective test in order to collect the human acceptability data for future sonic‐boom acceptability criteria.