2007 Volume 31 Issue 4 Pages 322-332
Finite difference time-domain method (FDTDM) was applied to examine the method for increasing the shielding effect of an inverted-L barrier against the bogie noise of Shinkansen. A numerical calculation by FDTDM was carried out assuming that the radiated sound from bogie parts propagated as a two-dimensional traveling wave. The results indicate that installing absorbing material to the inner side of the inverted-L barrier shows the maximum improvement effect and the attachment of absorbing object of 0.3m thickness on the top panel of the inverted-L barrier is more effective than the attachment of reflective straight barrier of 1m height on the same position. The results also suggest the potential acoustic energy around the edge part of barriers play an important roll in the shielding effect of barriers. These results obtained by FDTDM were confirmed by a three-dimensional 1/25 scale model experiment, and moreover by the field measurement carried out in the actual commercial line of the Tohoku Shinkansen.
