Hirokazu Shoji

Development of an advanced multi-material bird-strike model using the smoothed particle hydrodynamics method

This paper presents the results of simulations used to verify the smoothed particle hydrodynamics method for bird-strike simulation and assess the influence of the bird-model shape, internal organ structure and certification configurations by comparing traditional primitive models to a new model based on biometric and published CT-scan data. Initially, a series of analyses and sensitivity studies are performed for traditional models with air porosity which show the Hugoniot pressure, steady-state pressure, impulse and force history data are in close agreement with classical hydrodynamic theory. The new model which includes eight body parts and accounts for variations in density and material strength indicates a lower Hugoniot pressure and increased asymmetry during impact. The results of the new model also show that a bird in a representative flight configuration has a longer impact duration and higher peak impact force when compared to the current folded configuration used in certification testing and simulations.

Airframe noise measurements on JAXA Jet Flying Test Bed “Hisho” using a phased microphone array:

In 2015, the Japan Aerospace Exploration Agency launched the Flight demonstration of QUiet technology to Reduce nOise from High-lift configurations project to verify by flight demonstration the feasibility of practical noise-reducing aircraft modification concepts. In order to serve as a baseline for comparison before modification, airframe noise sources of the JAXA Jet Flying Test Bed “Hisho” were measured with a 30 m diameter array of 195 microphones mounted on a wooden platform built temporary beside the runway of Noto Satoyama Airport in Japan. A classical Delay and Sum in the time domain beamforming algorithm was adapted for the present study, with weight factors introduced to improve the low-frequency resolution and autocorrelations eliminated to suppress wind noise at high frequencies. In the landing configuration at idle thrust, the main landing gear, nose landing gear, and side edges of the six extended flap panels were found to be the dominant “Hisho” airframe noise sources. Deconvolution by the DAMAS and CLEAN-SC algorithms provided clearer positions of these sound sources at low frequencies. Integration of acoustical maps agreed well with the sound pressure level measured by a microphone placed at the center of the microphone array and gave detailed information about the contribution of each noise source.