Yamato NAGAI
Noise propagation Analysis Considering Noise absorbing material using Cellular Automataon Method
Yasuyuki MIYAKI
Noise is one of the important environmental problems. Solving these problems, it has been performed Noise propagation analysis and development of noise control technology. However, the technology that have versatility and simply is not developed very. Therefore, we have been developing the 2-dimensions noise propagation analysis that is used cellular automaton (CA) method in this research. In CA method, calculation area is divided into a cell of uniform size, and state value is calculated from time to time by applying local interaction rule to each relation between notice cell and adjoining cells.
Till last year, we compared CA model with theory value, Maekawa chart and finite difference method about some phenomena of sound (the divergence decrease, the diffraction attenuation, the interference and the Doppler effect) in 2-dimensions. In addition, we examined calculation time and stable condition of calculation. As a result, we found that the precision of CA was equal with finite difference method and CA was profitable to calculation time.However, it hasn't been evaluated quantitive .and because of considertation only full reflection , it is unsatisfactory in point of expressing real phenomenon because it has been considerated only full reflection.
Then, it is last purpose for this research to evaluate quantitive and consider Sound absorption nature material by using CA. In the result of research, in 2-dimmension , it turns out that it is able to evaluate quantitive and calculation solution in CA has as same as FEM and Analysis solution. On the other hand, in modeling of sound absorption nature material, if absorption coefficient is over 0.7, we understood that we need to further examination about modeling.
Please use "previous botton" to return the previous page