STUDY ON STRUCTURE OF SHOCK WAVES BY DIGITAL IMAGE PROCESSING AND BASIC RESEARCH ON MEASUREMENT TECHNOLOGY OF DIGITAL IMAGE

数字图像处理研究激波结构及数字图像测量技术基础研究

• 批准号: 11650194
• 负责人: KOJIMA Tadatomo
• 金额: $ 1.66万
• 依托单位: KINKI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650194/
• 关键词: Aerodynamic Acoustics; Subsonic Flow; Digital Image Processing; Discrete Frequency Noise; Jet Noise; Vortex Ring; Vortex Structure

The effect of the structure and behavior of vortex rings on jet noise containing discrete frequency has been studied by digital image processing. In particular, the behavior of a series of vortex rings released from a nozzle with divergent exit angle was clarified by a high-speed video camera including Schlieren systems. The structures of vortex rings were classified into the following phenomena : chasing phenomenon in which a leading vortex ring was chased by a released vortex ring, merging phenomenon in which a released vortex ring merged after passing-through to a leading vortex ring, and rolling up phenomenon in which the main flow was rapidly rolled up after contraction. It was found that the discrete frequency was affected considerably by the vortex structure and behavior, and the characteristic frequency distributions for the above phenomena were presented. Furthermore, in spite of considerably lower pressure, violent discrete frequency and screech noise such as that generated by a supersonic jet were generated.

通过数字图像处理研究了涡环的结构和行为对包含离散频率的射流噪声的影响。特别是，包括 Schlieren 系统的高速摄像机阐明了从具有发散出口角的喷嘴释放的一系列涡环的行为。涡环的结构分为以下几种现象：主涡环被释放涡环追赶的追赶现象、释放涡环经过主涡环后合并的合并现象、主流收缩后迅速卷起的卷起现象。研究发现，涡流结构和行为对离散频率有很大影响，并给出了上述现象的特征频率分布。此外，尽管压力相当低，但仍会产生剧烈的离散频率和刺耳噪音，例如超音速喷气机产生的噪音。

项目成果

児島忠倫: "非対称性をもつ不足膨張噴流中の擬似衝撃構造の解明"可視化情報学会誌. 19.S2. 259-262 (1999)

Tadamichi Kojima：“非对称欠膨胀射流中的伪激波结构的阐明”可视化信息学会杂志 19.S2 259-262 (1999)。

嶽間沢秀孝: "消音器内を伝播する衝撃波の構造と減衰特性"可視化情報学会誌. 20,S2. 205-208 (2000)

Hidetaka Takemazawa：“消音器中传播的冲击波的结构和衰减特性”视觉信息学会杂志 20，S2（2000）。

児島忠倫: "2個の非軸対称ノズルから噴出される超音速噴流の干渉特性に関する研究"近畿大学工学部研究報告. No.33. 105-110 (1999)

小岛忠道：“两个非轴对称喷嘴喷射的超音速射流的干涉特性研究”近畿大学工学部研究报告第33. 105-110号（1999）。

児島忠倫: "非対称性をもつ不足膨張噴流中の擬似衝撃波構造の解明"可視化情報学会誌. 19・S2. 259-262 (1999)

小岛忠通：“不对称的欠膨胀射流中的伪冲击波结构的阐明”可视化信息学会杂志 19・S2（1999）。

Tadatomo KOJIMA: "Relation between Structure of Pseudo-Shock Waves and discrete Frequency Noise (Analysis by Binary Image Method)"Transactions of The Japan Society of Mechanical Engineers. Vol.69 No.269. 78-85 (1999)

小岛忠友：“伪冲击波的结构与离散频率噪声的关系（二值图像法分析）”日本机械工程学会会刊。