Roughness And Correlation-Length Measurements Of Rough Surface Objects Using The Speckle Contrast In The Diffraction Field

1988 ◽  
Author(s):  
H. Kadono ◽  
T. Asakura ◽  
N. Takai
Keyword(s):  
Rough Surface ◽  
Correlation Length ◽  
Diffraction Field ◽  
Speckle Contrast ◽  
Length Measurements

Simulation on Composite Backscattering from Rough Surface with Target above it

2012 ◽  
Vol 490-495 ◽  
pp. 603-607
Author(s):  
Wei Tian ◽  
Xin Cheng Ren
Keyword(s):  
Rough Surface ◽  
Root Mean Square ◽  
Cross Section ◽  
Correlation Length ◽  
Rectangular Cross Section ◽  
Mean Square ◽  
Method Of Moment ◽  
Backscattering Coefficient ◽  
One Dimensional ◽  
Surface Fluctuation

One-dimensional Gaussion rough surface is simulated and employed by Monte Carlo Method, the composite backscattering from one-dimensional Gaussion rough surface with rectangular cross-section column above it is studied using Method of Moment. The curves of composite backscattering coefficient with scattering angle and frequency of incident wave are simulated by numerical calculation, the influence of the root mean square and the correlation length of rough surface fluctuation, the height between the center of the rectangular cross-section column and the rough surface, the length and the width of the rectangular cross-section column is discussed. The characteristic of the composite back-scatting from one-dimensional Gaussion rough surface with a rectangular cross-section column above it is obtained. The results show that the influences of the root mean square and the correlation length of rough surface fluctuation, the height between the center of the rectangular cross-section column and the rough surface, the width of the rectangular cross-section column on the composite backscattering coefficients are obvious while the influences of the length of the rectangular cross-section column on the complex backscattering coefficient is less.

Topography Analysis of Random Anisotropic Gaussian Rough Surfaces

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Deepak K. Prajapati ◽  
Mayank Tiwari
Keyword(s):  
Standard Deviation ◽  
Rough Surface ◽  
Correlation Length ◽  
Rough Surfaces ◽  
Spectral Moments ◽  
Statistical Characterization ◽  
Wear Process ◽  
Increase With Increase ◽  
Bandwidth Parameter ◽  
Significant Difference

Engineered surfaces (ground and similarly structured rough surfaces) show anisotropic characteristics and their topography parameters are direction dependent. Statistical characterization of these surfaces is still complex because of directional nature of surfaces. In this technical brief, an attempt is made to simulate anisotropic surfaces through use of topography parameters (three-dimensional (3D) surface parameters). First, 3D anisotropic random Gaussian rough surface is generated numerically with fast Fourier transform (FFT). Numerically generated anisotropic random Gaussian rough surface shows statistical properties (texture direction, texture ratio) similar to ground and similarly directional anisotropic rough surfaces. For numerically generated anisotropic Gaussian rough surface, important 3D roughness parameters are determined. Sayles and Thomas' (1976, “Thermal Conductance of Rough Elastic Contact,” Appl. Energy, 2(4), pp. 249–267.) theoretical model for directional anisotropic rough surface is adopted here for calculating the summit parameters, i.e., equivalent bandwidth parameter, mean summit curvature, skewness of summit height, standard deviation of summit height, and equivalent spectral moments. This work demonstrates the variation of spectral moments in both across and parallel to the lay directions with pattern ratio (γ=βx/βy). Correlation length (βx) is fixed 10μm and correlation length (βy) is varied from 100 to 10 μm. Variation of summit parameters with pattern ratio is also discussed in detail. Results shows that mean summit curvature and skewness of summit heights increase with increase in pattern ratio, whereas standard deviation of summit heights and equivalent bandwidth parameter (αe) decreases with pattern ratio. A significant difference is found in “Abbott-Firestone” parameters when calculated in both perpendicular and parallel to lay directions. Effect of these parameters on wear process is discussed in brief.

scholarly journals Master singular behavior from correlation length measurements for seven one-component fluids near their gas-liquid critical point

2006 ◽  
Vol 73 (2) ◽  
Author(s):  
Yves Garrabos ◽  
Fabien Palencia ◽  
Carole Lecoutre ◽  
Can Erkey ◽  
Bernard Le Neindre
Keyword(s):  
Critical Point ◽  
Correlation Length ◽  
Singular Behavior ◽  
Length Measurements
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