Structure and Oscillation of Underexpanded Jet

• 作者: Hiromasa Suzuki Masaki Endo Yoko Sakakibara
• 来源期刊: 流体动力学(英文)
• 学科: 数学
• 关键词: Underexpanded JET PLATE Shock INCIDENT Shock VISUALIZATION TVD Scheme
• 年，卷（期）: ltdlxyw,（2）
• 页码范围: 85-91
• 页数: 7页
• 分类号: O1

摘要

In this study, flow characteristics are experimentally and numerically discussed, especially concerning shock-cell structure and oscillatory phenomena of supersonic jet. The jet becomes underexpanded when the nozzle pressure ratio of convergent nozzle exceeds the critical value. The underexpanded jet is not uniform because of the presence of the expansion wave, the compression wave and the shock wave formed in it. Many vortices are induced in jet boundary region by shearing stress generated between supersonic jet flow and atmospheric air. They interact with shock waves composing cell node of jet, which is closely related to a noise radiating from the jet. In experiment, flow field is visualized and the shape of cell structure is examined. Furthermore, frequency of vortex generation is measured. The jet is simulated using TVD scheme and the results are compared with the experimental ones. Distortion of cell structure caused by three dimensional oscillation of jet and behavior of vortices are discussed.