World first prediction of the sound radiating from a recorder

Hiroshi Yokoyama and his colleagues at Department of Mechanical Engineering, Toyohashi University of Technology, in collaboration with researchers at YAMAHA Corporation, have achieved a world first, in accurately predicting the sound radiating from a recorder. (Figure 1, Movie 1). The calculations for this study took two weeks using about 100 nodes of supercomputers (FX10 in Tokyo University or Kyushu University). It was a huge computational cost.

In air-reed instruments such as a recorder, the flow velocity fluctuates according to the blowing of the performer. These fluctuations generate sound (pressure and density fluctuations). It had been understood that a small change in the shape or material of the instruments could critically affect the ease of playing or how a performer felt during performance. However, the detailed relationship between the shape or material and the sound had not been clarified, and the reason why they affected the tones was unknown.