Two-dimensional shear dispersion for skewed flows in narrow gaps between moving surfaces

1990 ◽  
Vol 214 (-1) ◽  
pp. 211 ◽  
Author(s):  
Ronald Smith
Keyword(s):  
Two Dimensional ◽  
Shear Dispersion ◽  
Narrow Gaps

scholarly journals Numerical modeling of fluid resonance in narrow gaps of fixed rectangular structures

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401987230
Author(s):  
Ming-ming Liu ◽  
Rui-jia Jin ◽  
Zhen-dong Cui
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Stokes Equations ◽  
Theoretical Data ◽  
Numerical Results ◽  
Two Dimensional ◽  
Arbitrary Lagrangian Eulerian ◽  
Fluid Resonance ◽  
Resonance Wave ◽  
Narrow Gaps

A two-dimensional numerical model is developed to investigate the phenomenon of resonance in narrow gaps. Instead of using commonly used Volume of Fluid method to capture the free surface which is sometimes difficult to capture the geometric properties of the geometrically complicated interface, the free surface is traced by using Arbitrary Lagrangian–Eulerian method. The numerical model is based on the two-dimensional Reynolds-Averaged Navier–Stokes equations. The numerical model is validated against wave propagation in wave flume. Comparisons between the numerical results and available theoretical data show satisfactory agreements. Fluid resonance in narrow gaps of fixed rectangular structures are simulated. Numerical results show that resonance wave height and wave frequency for rectangle boxes with sphenoid corners is larger than for rectangle boxes.

scholarly journals Comparisons of Two Types of Particle Tracking Models Including the Effects of Vertical Velocity Shear

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3535
Author(s):  
Inhwan Park ◽  
Jaehyun Shin ◽  
Hoje Seong ◽  
Dong Sop Rhee
Keyword(s):  
Particle Tracking ◽  
Analytic Solution ◽  
Initial Period ◽  
Computation Method ◽  
Two Dimensional ◽  
Fick’S Law ◽  
Dispersion Process ◽  
Fick's Law ◽  
Shear Dispersion ◽  
Tracking Model

In this study, two types of particle tracking models were presented to investigate the applicability in the two-dimensional solute mixing simulations. The conventional particle tracking model, denoted as PTM, was developed based on Fick’s law, which adopted the dispersion coefficient to calculate the random displacements. The other model is the particle dispersion model (PDM), which computes the shear dispersion process by dividing into two computation procedures as the shear translation and the vertical mixing. The PTM and the PDM included the effects of vertical profiles of velocity in the computation of dispersion coefficients and the shear translation step, respectively. The main difference between the two models is whether the shear dispersion process is reproduced using Fick’s law or the direct computation method. These differences were clearly revealed by comparing with the analytic solution of the advection-dispersion equation. The concentration curve resulting from the PTM shows the Gaussian curves, which were well-fitted with the analytic solution in both initial and Taylor periods. Meanwhile, the PDM presented skewed curves in the initial period and gradually turned to the symmetric shape in the Taylor period. The inherent differences of the two particle tracking models were scrutinized against the two-dimensional tracer test results, which show the non-Fickian mixing properties. The comparisons of concentration–time curves reveal that the PDM reproduced a more accurate shape of the curves than the results by the PTM by demonstrating skewed concentration curves.

The split ring resonator

2010 ◽  
Vol 466 (2123) ◽  
pp. 3117-3134 ◽  
Author(s):  
Stefan G. Llewellyn Smith ◽  
Anthony M. J. Davis
Keyword(s):  
Ring Resonator ◽  
Split Ring Resonator ◽  
Acoustic Mode ◽  
Two Dimensional ◽  
Algebraic Equations ◽  
Split Ring ◽  
Concentric Circles ◽  
Square Array ◽  
Narrow Gaps ◽  
Rayleigh Mode

We obtain band diagrams for a two-dimensional periodic structure consisting of an infinite square array of infinitely thin concentric circles (split rings) with narrow gaps. Our approach exploits the narrowness of the gaps and yields algebraic equations relating the frequency to the Bloch wavenumber and geometric properties of the array. Further asymptotic analysis indicates that the gravest mode has a frequency that scales in an inverse logarithmic fashion with the size of the gap and that exhibits anomalous dispersion. Near the origin of the Brillouin zone this ‘acoustic’ mode is dispersionless. Numerical solution of the eigenvalue problem in the single-gap case confirms these conclusions. The two lowest modes of the split ring can be interpreted as a splitting of the gravest propagating Rayleigh mode.

scholarly journals Holistic discretisation of shear dispersion in a two-dimensional channel

2003 ◽  
Vol 44 ◽  
pp. 512 ◽  
Author(s):  
T. MacKenzie ◽  
A. J. Roberts
Keyword(s):  
Two Dimensional ◽  
Shear Dispersion

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Analysis of the 9th November 1990 flare

2000 ◽  
Vol 179 ◽  
pp. 229-232
Author(s):  
Anita Joshi ◽  
Wahab Uddin
Keyword(s):  
Image Processing ◽  
Two Dimensional ◽  
Temporal Behaviour ◽  
Contour Maps ◽  
Dimensional Measurements ◽  
Processing Software ◽  
Image Processing Software

AbstractIn this paper we present complete two-dimensional measurements of the observed brightness of the 9th November 1990Hαflare, using a PDS microdensitometer scanner and image processing software MIDAS. The resulting isophotal contour maps, were used to describe morphological-cum-temporal behaviour of the flare and also the kernels of the flare. Correlation of theHαflare with SXR and MW radiations were also studied.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

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