Wavelet Multi-Resolution Analysis of Coherent Structure in a Jet Issuing From Rotating Circular Pipe With Inclined Section

2002 ◽  
Author(s):  
Masahiro Nakashima ◽  
Hui Li ◽  
Takahide Tabata ◽  
Tsutomu Nozaki
Keyword(s):  
Coherent Structure ◽  
Circular Pipe ◽  
Turbulent Structures ◽  
Rotating Speed ◽  
Multi Scale ◽  
The Core ◽  
Multi Resolution Analysis ◽  
Flow Feature ◽  
Resolution Analysis ◽  
Inclined Angle

The flow feature of the jet issuing from the circular pipe with the rotating inclined section has been investigated by the method of the flow visualization and the image processing. It has been found that the jet diffusion is affected by the inclined angle and the rotating speed. The coherent structure of the jet has been also studied by using the wavelet multi-resolution analysis. The multi-scale turbulent structures were visualized and the core and edge of the vortex were identified at different broad scales.

APPLICATION OF WAVELET MULTIRESOLUTION ANALYSIS TO JET FLOW ISSUING FROM ROTATING CIRCULAR PIPE WITH INCLINED SECTION

2006 ◽  
Vol 04 (02) ◽  
pp. 311-319 ◽  
Author(s):  
MASAHIRO NAKASHIMA ◽  
AKIRA (HUI LI) RINOSHIKA ◽  
TAKAHIDE TABATA ◽  
TSUTOMU NOZAKI
Keyword(s):  
Image Processing ◽  
Multiresolution Analysis ◽  
Coherent Structure ◽  
Circular Pipe ◽  
Turbulent Structures ◽  
Rotating Speed ◽  
The Core ◽  
Flow Feature ◽  
Wavelet Multiresolution Analysis ◽  
Inclined Angle

The flow feature of the jet issuing from the circular pipe with the rotating inclined section has been investigated by the methods of flow visualization and image processing. It has been found that the jet diffusion is affected by the inclined angle and the rotating speed. The coherent structure of the jet has also been studied by using wavelet multiresolution analysis. The multiscale turbulent structures were visualized and the core and edge of the vortex were identified at different broad scales.

Wavelet Multi-Resolution Image Analysis on a Jet Issuing From Rotating Inclined Section

2003 ◽  
Author(s):  
Masahiro Nakashima ◽  
Takahide Tabata ◽  
Hui Li ◽  
Tsutomu Nozaki
Keyword(s):  
Volume Rendering ◽  
Large Scale ◽  
Three Dimensional ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Resolution Method ◽  
Rotating Speed ◽  
Multi Resolution Analysis ◽  
Resolution Analysis ◽  
Inclined Angle

The water jet flow issuing from the rotating circular pipe with the inclined section has been studied by the method of the flow visualization and the wavelet multi-resolution method. Three-dimensional views of large-scale structure in the jet cross-section were constructed by applying a volume rendering method to the images of the sum of wavelet levels 1 and 2 in layers in the wavelet multi-resolution analysis. In order to clarify the change with the time of the jet diffusion, the large-scale structure has been investigated in the cases of various inclined angles of the section and rotating speeds of the pipe. As a result, it has been found that the jet diffusion is affected by the inclined angle and the rotating speed of the pipe.

Visualization of Three-Dimensional Turbulent Structure Based on Orthogonal Wavelet Decomposition

2003 ◽  
Author(s):  
Hui Li ◽  
Hui Hu ◽  
Toshio Kobayashi ◽  
Tetsuo Saga ◽  
Nobuyuki Taniguchi
Keyword(s):  
Digital Imaging ◽  
Wavelet Decomposition ◽  
Three Dimensional ◽  
Time Varying ◽  
Orthogonal Wavelet ◽  
Turbulent Structures ◽  
Vortical Structures ◽  
Multi Scale ◽  
Multi Resolution Analysis ◽  
Resolution Analysis

The orthogonal multi-resolution analysis was applied to the digital imaging photographs of lobed mixing jets for revealing the time varying turbulent structures of various scales. The image components of five different broad scales are obtained, and each image components can provide information on the multi-scale turbulent structures. The complex vortical structures of various scales were clearly extracted and visualized at different instances.

Study on Jet Flow Issuing From Pipe With Rotating Inclined Section

2003 ◽  
Author(s):  
Masahiro Nakashima ◽  
Hui Li ◽  
Takahide Tabata ◽  
Tsutomu Nozaki
Keyword(s):  
Image Processing ◽  
Flow Visualization ◽  
Jet Flow ◽  
Water Jet ◽  
Circular Pipe ◽  
Rotating Speed ◽  
Plane Normal ◽  
Inclined Angle

The water jet flow issuing from the rotating circular pipe with the inclined section has been studied by the method of the flow visualization and the image processing. The velocity distributions and the width of the jet have been measured in the cases of various inclined angles of the section and rotating speeds of the pipe. The effects of these variables on the jet diffusion have been clarified by measuring the jet width obtained from the superimposed images in the plane normal to the jet flow. As a result, it has been found that the jet diffusion is affected by the inclined angle and the rotating speed of the pipe. Furthermore, it has been clarified that there exists the rotating speed showing the effects of the rotating inclined section remarkably.

Wavelet-based multi-scale finite element modeling and modal identification for structural damage detection

2017 ◽  
Vol 20 (8) ◽  
pp. 1185-1195 ◽  
Author(s):  
Wen-Yu He ◽  
Songye Zhu ◽  
Zhi-Wei Chen
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Detection ◽  
Structural Damage ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Modal Identification ◽  
Multi Scale ◽  
Multi Resolution Analysis ◽  
Resolution Analysis

Wavelet techniques enable multi-resolution analysis that can represent a function (either field or signal function) in a multi-scale manner. This article presents a damage detection method with dynamically changed scales in both temporal and spatial domains, by taking advantage of the wavelet-based multi-resolution analysis. This method combines a wavelet-based finite element model (WFEM) that employs B-spline wavelet as shape functions and wavelet-based modal identification method to detect structural damage progressively. High-fidelity modal information can be computed or identified with minimized computation cost by lifting the wavelet scales in the wavelet-based finite element model and in signal processing individually according to the actual requirements. Numerical examples demonstrate that the accuracy of damage detection is improved considerably by this lifting strategy during the damage detection process. Besides, fewer degrees of freedom are involved in the wavelet-based finite element model than those of traditional finite element method. The computational efficiency can be improved to large extent and computation resources can be utilized more rationally using the proposed multi-scale approach.

Image Fusion Algorithm Based on Contourlet Transform

2014 ◽  
Vol 1044-1045 ◽  
pp. 1173-1177
Author(s):  
Yu Kun Zhang ◽  
Shu He ◽  
Yong Jun Cheng
Keyword(s):  
Image Fusion ◽  
Spatial Resolution ◽  
Contourlet Transform ◽  
Analysis Tool ◽  
Fusion Algorithm ◽  
Multi Scale ◽  
Multi Resolution Analysis ◽  
Resolution Analysis ◽  
Application Requirements ◽  
Image Fusion Method

Contourlet transform is a new multi-scale, multi-resolution analysis tool. This paper studied on the theory of Contourlet transform.,According to the practical application requirements of characteristics of data, much details in complex images it propose a novel image fusion method of remote sensing images based on contourlet Coefficients correlativity of directional region. Besides improving fused images spatial resolution, our method can better preserve original multi-spectral image’s color information.Extensive experimental results show that the proposed method is superior to conventional methods in terms of entropy, joint entropy, and average gradient. It can enhance the spatial resolution of target images. Meanwhile, it well preserves the color information of multi-spectral images.

scholarly journals Multi-scale analysis of bias correction of soil moisture

2014 ◽  
Vol 11 (7) ◽  
pp. 8995-9026
Author(s):  
C.-H. Su ◽  
D. Ryu
Keyword(s):  
Soil Moisture ◽  
Bias Correction ◽  
Spatiotemporal Variability ◽  
Nonlinear Method ◽  
Multi Scale ◽  
Bias Model ◽  
Multi Resolution Analysis ◽  
Resolution Analysis ◽  
Data Adaptive

Abstract. Remote sensing, in situ networks and models are now providing unprecedented information for environmental monitoring. To conjunctively use multi-source data nominally representing an identical variable, one must resolve biases existing between these disparate sources, and the characteristics of the biases can be non-trivial due to spatiotemporal variability of the target variable, inter-sensor differences with variable measurement supports. One such example is of soil moisture (SM) monitoring. Triple collocation (TC) based bias correction is a powerful statistical method that increasingly being used to address this issue but is only applicable to the linear regime, whereas nonlinear method of statistical moment matching is susceptible to unintended biases originating from measurement error. Since different physical processes that influence SM dynamics may be distinguishable by their characteristic spatiotemporal scales, we propose a multi-time-scale linear bias model in the framework of a wavelet-based multi-resolution analysis (MRA). The joint MRA-TC analysis was applied to demonstrate scale-dependent biases between in situ, remotely-sensed and modelled SM, the influence of various prospective bias correction schemes on these biases, and lastly to enable multi-scale bias correction and data adaptive, nonlinear de-noising via wavelet thresholding.

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