多孔形低騒音弁の減音の効率化に関する研究 : 第3報,ステップ孔にIおける減音機構と超音速噴流の構造

概要

論文の詳細を見る
Supersonic jet flows near the abrupt enlarged exit of a step hole on the occurrence of noise reduction have been studied experimentally and theoretically to clarify the principle of the noise reduction and to estimate the operating condition. The so-called λ-type or X-type shock wave progression is observed in the supersonic jet flow by schliren photography. A theoretical model of the shock wave patterns is developed and analyses on the flow field around the shock wave are performed. From the fact that the theoretical flow velocity just downstream of the shock wave shows strong correlation to the measured noise reduction, it is clearly concluded that the noise reductions are due to the reduction of jet exhaust velocity through the strong shock wave. Also, the theoretical model can estimate the operating condition where the noise reduction occurs, and facilitate the design of an acoustically improved step hole.
一般社団法人日本機械学会の論文
1989-12-25