Sound field analysis based on acoustic wave theory and its auralization using VR technology

  • Kashiyama, Kazuo (Chuo University)
  • Fukazawa, Kazushi (Chuo University)
  • Miyauchi, Haruki (Chuo University)

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The evaluation of noise is very important for planning and designing of various construction works in an urban area. There have been presented a number of evaluation methods for noise simulation. Based on the frame of reference used, those methods can be classified into two categories: 1) Methods based on the geometrical acoustic theory and 2) Methods based on acoustic wave theory. Both methods have advantages and disadvantages. For the methods based on the geometrical acoustic theory, the CPU time is very short but the numerical accuracy is low comparing with the methods based on the acoustic wave theory. On the other hand, the method based on the acoustic wave theory gives accurate solution but the simulation becomes a large scale simulation. In the conventional studies, the computed noise level is described by the visualization using computer graphic such as iso-surface. Although the visualization is a powerful tool to understand the distribution of noise, it is difficult to recognize the noise level intuitively. In this presentation, a noise evaluation system based on acoustic wave theory. This paper utilizes two methods; the finite element method and the boundary element method using a fast multipole method, which are employed for the discretization of unsteady wave equation. The system exposes to the users the computed noise level with both the auditory information using sound source signal and the visual information using CG image. In order to investigate the validity and efficiency of the method, the present method is applied to several noise problems in various construction works. The computed results are compared with the measurement results in VR space. The present system is useful for planning and designing tool for various constructions works in an urban area, and also for consensus building for designers and the local residents.