TURBULENCE MEASUREMENT OF A LOW-DENSITY SUPERSONIC JETS WITH A LASER-INDUCED FLUORESCENCE METHOD

激光诱导荧光法测量低密度超声速射流湍流

• 批准号: 63550139
• 负责人: MASUDA Mitsuharu
• 金额: $ 1.34万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550139/
• 关键词: RAREFIED FLOW; SUPERSONIC JETS; LASER-INDUCED FLUORESCENCE; TURBULENT TRANSITION; レーザ誘起蛍光法

The fluctuations of the flow parameters in the supersonic freejets play dominant role in the generation of noise and/or vibration. Therefore, it is important to clarify the characteristics of these fluctuations. The fluctuations in a jet are generated in the shear layer of the jet boundary as the backpressure is increased. To investigate fluctuations, it is desirable to perform experiments with nonintrusive diagnostic methods. In the present research, the laser-induced fluorescence method was used to measure the fluctuations of low-density axisymmetric argon jets with high spatial and temporal resolution. With this technique, the following results were obtained.1. By changing the pressure ratio across a sonic orifice, the generation and distribution of turbulence in the jet were investigated. It was found that the turbulence was generated in the shear layer of the jet boundary, and its intensity was maximum in the periphery of the Mach disk. The turbulence was also found to be generate … More d with the Reynolds number based on the orifice exit condition above 4000.2. With the data acquisition system developed in the present research, the probability density function, auto-correlation function and power spectral density function were obtained, and the statistical characteristics of the fluctuation was clarified. Also, by chopping the laser beam by an acoustooptic modulator, the cross-correlation function was obtained.3. The analysis of the power spectral density function showed that the dominant spectrum existed near 3kHz, and the intensity of this spectrum depended on the orifice shape.4. With the detailed analyses of the power spectral density, auto-correlation and cross-correlation functions, it was found that the fluctuation generated in the shear layer was propagated in the downstream direction. However, the dominant frequency of the fluctuation was an order of magnitude lower than that was expected by the existing stability theory. This point seems to need further investigation. Less

超声速自由射流中流动参数的波动对噪声和/或振动的产生起着主导作用。因此，弄清这些波动的特征是很重要的。随着背压的增加，射流中的波动在射流边界的剪切层中产生。为了研究波动，最好用非侵入性诊断方法进行实验。本文采用激光诱导荧光法对轴对称低密度氩射流的脉动进行了高时空分辨率的测量。通过该技术，获得了以下结果。1.通过改变声孔压比，研究了射流中湍流的产生和分布。结果表明，湍流产生于射流边界的剪切层，其强度在马赫盘周边最大。湍流也被发现产生 ...更多信息 d，雷诺数基于大于4000.2的孔出口条件。利用自行研制的数据采集系统，获得了该波动的概率密度函数、自相关函数和功率谱密度函数，阐明了该波动的统计特征。同时，通过声光调制器对激光束进行斩波，得到了互相关函数.功率谱密度函数分析表明，在3 kHz附近存在一个主频谱，其强度与小孔形状有关.通过对功率谱密度、自相关函数和互相关函数的分析，发现剪切层中产生的脉动是向下游方向传播的。然而，波动的主频率比现有稳定性理论预期的低一个数量级。这一点似乎需要进一步调查。少

项目成果

益田光治: 衝撃工学シンポジウム講演論文集. 196-201 (1988)

Mitsuharu Masuda：冲击工程研讨会演讲记录 196-201 (1988)。

松本芳幸: "レ-ザ誘起蛍光法による希薄超音速噴流境界部の乱れ発生に関する研究" 流れの可視化. 9. 297-300 (1989)

Yoshiyuki Matsumoto：“使用激光诱导荧光方法研究稀超音速射流边界处的湍流生成”流动可视化。 9. 297-300 (1989)

MASUDA, Mitsuharu: "Distribution of Turbulence in a Low-density Supersonic Jets Found by a Laser-induced Fluorescence Method" Proc.National Symp.Shock Wave Phenomena, pp.139-148, 1989.

MASUDA, Mitsuharu：“激光诱导荧光方法发现的低密度超音速射流中的湍流分布”Proc.National Symp.Shock Wave Phenomena，第 139-148 页，1989 年。

MASUDA, Mitsuharu: "Fluctuation Measurement of Rarefied Supersonic Freejets with Laser-induced Fluorescence Method" Proc.Shock Tube Symp.196-201 (1988)

MASUDA, Mitsuharu：“用激光诱导荧光法测量稀薄超音速自由射流的波动”Proc.Shock Tube Symp.196-201 (1988)

MASUDA, Mitsuharu: "Turbulence Measurement of a Low-density Supersonic Jet with a Laser-induced Fluorescence Method" Progress in Astro. Aero., 117, pp.149-156, 1989.

MASUDA、Mitsuharu：“用激光诱导荧光方法测量低密度超音速射流的湍流”Astro 进展。