The Japan Aerospace Exploration Agency (JAXA) has validated its original low sonic boom design concept through a flight test for the first time in the world*1. This has been confirmed through an analysis of the sonic boom signatures measured during the flight test of the D-SEND#2, the second phase of the „Drop test for the Simplified Evaluation of Non-symmetrically Distributed sonic boom (D-SEND)”. The flight test of D-SEND#2 was carried out on July 24, 2015 (local time) at the Esrange Space Center in Sweden.
A sonic boom is a phenomenon caused by shockwaves generated by supersonic flight, which propagates to the ground as impulsive sound. Measures to reduce the sonic boom have been on the global agenda as a key to realizing future supersonic civil transport. In response, JAXA has been researching and developing its original low sonic boom design concept together with enabling design methods, the feasibility of which have now been validated through the D-SEND project. JAXA has also obtained associated technologies and data on the sonic boom that can contribute to the standards formulation for the sonic boom.
JAXA has also confirmed that the measured sonic boom signatures from the flight test show the effects of sonic boom reduction. The detailed analysis of low sonic boom signatures was carried out by taking into account the influences of atmospheric turbulence*2 on propagation of sonic booms and by developing a new analysis tool that enables to estimate such influences. It is the first time in the world that the influence of atmospheric turbulence on propagation of low sonic boom signatures has been analyzed.
JAXA will present its findings to ICAO (International Civil Aviation Organization) to accelerate the deliberation of international standardization of the sonic boom. JAXA intends to further promote activities that lead to the realization of future supersonic civil transport in cooperation with the aviation industry.
*1: The flight test of the D-SEND#2 is the world’s first successful experimental airplane flight in which reduction of both front and rear shockwaves has been validated. JAXA’s original low sonic boom design technology can reduce the sonic boom of the Concorde by half. If applying to a small supersonic civil transport machine for 50 passengers, the sonic boom can be reduced by one quarter.
*2: Atmospheric turbulence: This means both time and space-wise fluctuations of aerial speed and temperatures in the atmosphere, occurring at an altitude of a few kilometers from the Earth’s surface. It is known that atmospheric turbulence occurs more frequently over the uneven surface covered by buildings or forests, and during the daytime, rather than nighttime, when differences in temperature in the atmosphere and on the ground are greater.
Source / Author: JAXA