基于DFT的水射流红外热像频域时空分析

宫伟力; 赵海燕; 安里千; 毛灵涛

基于DFT的水射流红外热像频域时空分析

中国矿业大学(北京) 力学与建筑工程学院, 北京 100083

基金项目: 国家重点基础研究发展规划(973)资助项目(2002CB412700)

详细信息

作者简介:
宫伟力(1955-),男,辽宁本溪人,副教授, gwl@cumtb.edu.cn.

中图分类号: TD 921.5
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出版历程
- 收稿日期: 2007-05-14
- 网络出版日期: 2008-06-30

Temporal and spatial analysis of infrared images from water jet in frequency domain based on DFT

School of Mechanics and Civil Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

摘要

摘要: 基于二维离散傅里叶变换及空间频谱分析,对水射流湍流脉动的空间尺度进行了研究,得到了由红外辐射温度表征的被动标量湍流场在对流区、耗散区、惯性子区的特征空间尺度及其时间演化规律.对射流不同区域的关心点重新采样,得到湍流场中关心点的时间序列,利用一维离散傅里叶变换,分析了对流区大尺度涡中心、惯性子区小尺度涡中心、耗散区及射流轴心线上各关心点的湍流波动特征.计算了时间序列频谱的分形维数,研究了自由湍流不同尺度区间上述各关心点湍流脉动的分形特征.
- 湍流 /
- 离散傅里叶变换 /
- 频谱分析 /
- 分形
Abstract: Based on 2-D discrete Fourier transforms (DFT) of infrared images from water jet and the analyses of its 2-D spatial spectrum, investigations were made on the spatial scales of passive scalars turbulent flow in high pressure water jet fields, which are represented by infrared images. The characteristic length scales and the law of their temporal evolution process were obtained in the energy (or convection) range, the dissipation range and the inertial range in between. Based on 1-D DFT, the turbulent temporal fluctuation characteristics were obtained for the interest points at large scale eddy center in convection range, sub-scale eddy center in inertial range, dissipation range, as well as in the axis of the jetting flow. In addition, the fractal dimensions were also calculated upon the 1-D spectrum, which was then used for fractal characterization of temporal fluctuations of the interest points in different scale regions of the scalars turbulent flow.
- turbulent flow /
- discrete Fourier transforms /
- spectrum analysis /
- fractals

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参考文献(1)

[1] 李国华,吴立新,吴淼,等.红外热像技术及其应用的研究进展[J].红外与激光工程,2004,33(3):227-230 Li Guohua, Wu Lixin, Wu Miao, et al. Current status and applications of infrared thermo graphy [J]. Infrared and Laser Engineering, 2004,33(3):227-230(in Chinese) [2] Bouchardy A M. Processing of infrared thermal image for aerodynamic research [J]. Applications of Digital Image Processing, 1983, 397:304-309 [3] Cehlin M, Moshfegh B, Sandberg M. Measurements of air temperatures close to a low-velocity diffuser in displacement ventilation using an infrared camera [J]. Energy and Buildings, 2002, 34:687-698 [4] Turner J S. Turbulent entrainment:the development of the entrainment assumption and its application to geophysical flows [J]. Fluid Mechanics, 1986, 373:431-471 [5] Hamzah M A, Lin Mengshi, Anna G C. Fourier transform infrared spectroscopy, detection and identification of Escherichia coli O157:H7 and Alicyclobacillus strains in apple juice [J]. International Journal of Food Microbiology, 2006, 111:73-80 [6] Patterson B M, Danielson N D, Sommer A J. Polymer mediated capillary electrophoresis with attenuated total reflectance infrared microspectroscopy detection[J]. Analytica Chimica Acts, 2007, 583:231-238 [7] William K P.数字图像处理[M]. 邓鲁华,张延恒,译.北京:机械工业出版社,2005 William K P. Digital image processing [M]. Translated by Deng Luhua, Zhang Yanheng. Beijing:China Machine Press, 2005(in Chinese) [8] 张兆顺,崔桂香,许春晓. 湍流理论与模拟[M]. 北京:清华大学出版社,2005 Zhang Zhaoshun, Cui Guixiang, Xu Chunxiao. Theory and modeling of turbulence [M]. Beijing:Tsinghua University Press, 2005 (in Chinese) [9] 肯尼思·法尔科内. 分形几何——数学基础及其应用[M]. 曾文曲,译.沈阳:东北大学出版社,2001:57-58 Falconer K J. Mathematical foundations and applications [M]. Translated by Zeng Wenqu. Shenyang:Northeast University Press, 2001:57-58 (in Chinese)

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