挿入管のある空洞形消音器内の流動パターン

2次気流騒音特性に及ぼす影響

抄録

The flow patterns in the cylindrical expansion chamber mufflers inserted an inlet pipe or a tail pipe respectively first were visualized by means of a spark tracing method, a smoke wire method and a tuft grid method. The patterns of the main stream in these mufflers are determinded by the ratio of the distance between both open ends of the inlet pipe and the tail pipe to pipe diameter. The frequency characteristics of flow noise generated secondarily in the mufflers vary with the above mentioned flow-patterns. The over all levels of flow noise for the tailpipe-inserted mufflers show moderately high values in the wide range of frequency as compared with those of the inletpipe-inserted mufflers, owing to the occurrence of the very complicated flow in the surroundings of the inner tail pipe.