250 曲がりダクトにおけるスプリッタによる高次モード波の低減(G05-4 流体騒音,G05 流体工学)  [in Japanese] 250 Sound Reduction of Higher Mode in Curved Duct with Splitter  [in Japanese]

The sound characteristics of the transmitted higher-mode waves through the three dimensional curved duct with a splitter have been studied for various lengths and locations of the splitter. A finite difference method for a linearized Euler equation is performed to obtain the sound pressure level (SPL) and time-averaged intensity splitter placed near outer wall of duct can reduce the transmitted power remarkably at a particular length of nearly constant ratio to the wave-length. On the other hand, the splitter placed at the center of the duct yields little reduction of the transmitted power. This is distinct from the case of fundamental plane wave, in which the variation of the splitter location has little effect on the tramsmitted power.