scholarly journals Applications of Two-Dimensional Spatial Routing Procedure for Estimating Dispersion Coefficients in Open Channel Flows

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1394
Author(s):  
Jaehyun Shin ◽  
Dongsop Rhee ◽  
Inhwan Park
Keyword(s):  
Open Channel ◽  
Test Case ◽  
Two Dimensional ◽  
Dispersion Coefficients ◽  
Stream Tube ◽  
Measured Concentration ◽  
Mixing Properties ◽  
Meandering Channel ◽  
Concentration Time ◽  
Routing Methods

In this study, the performance of two routing procedures were evaluated to estimate the two-dimensional dispersion coefficients. The two-dimensional Stream-Tube Routing Procedure (2D ST-RP) has been widely used to obtain the dispersion coefficients from measured concentration-time curves under the frozen cloud assumption. Meanwhile, the Spatial Routing Procedure (2D S-RP) employs the spatial distributions of concentration to estimate the dispersion coefficients. The performance of the two routing methods were evaluated in aspect of the validity of the frozen cloud assumption and the applicability in the non-Fickian mixing. From the estimation results of dispersion coefficients, the results by the 2D ST-RP included errors due to skewed concentration-time curves which were created by violating the frozen cloud assumption. On the other hand, the 2D S-RP provides accurate dispersion coefficients in the same condition. The estimated results of dispersion coefficients in the meandering channel show that both the 2D ST-RP and the 2D S-RP contained errors due to the non-Fickian mixing properties of the test case. Even with the discrepancies, the 2D S-RP presented more appropriate spatial variabilities along the meander cycle than the results by the 2D ST-RP.

Measurements of coastal dispersion in Ontario lakes

1976 ◽  
Vol 3 (1) ◽  
pp. 156-162 ◽  
Author(s):  
Merv. D. Palmer
Keyword(s):  
Cross Sections ◽  
Coastal Waters ◽  
Relative Dispersion ◽  
Concentration Profiles ◽  
Two Dimensional ◽  
Dispersion Coefficients ◽  
Measured Concentration ◽  
Power Growth ◽  
Constant Rate ◽  
Vertical Dispersion

A series of dye injection experiments were carried out near the surface in the coastal waters of lakes Erie, Ontario, and Simcoe. The purpose of the experiments was to determine whether the relative dispersion in these regions was similar to that obtained in other oceanographical experiment. Rhodamine BA dye was injected at a constant rate (approximately 150 mg/s) at a depth 1 m below the surface from a raft anchored in 9 m of water (approximately 1.5 km offshore) for 6 to 8 h. Two-dimensional dye plume concentrations were measured at cross sections 60 to 830 m from the source. Relative dispersion coefficients were determined numerically from the measured concentration profiles. The horizontal dispersion coefficients (80 to 4100 cm2/s) were comparable to oceanographical values and exhibited a 1.33 power growth with distance from the source. Vertical dispersion coefficients were very small (less than 1 cm2/s) and relatively independent of distance from the source.

Statement spectrum with two dimensional eigenvalues for intelligent software fault localization

2021 ◽  
pp. 1-16
Author(s):  
Shengbing Ren ◽  
Xing Zuo ◽  
Jun Chen ◽  
Wenzhao Tan
Keyword(s):  
Neural Network ◽  
Feature Extraction ◽  
Rbf Neural Network ◽  
Fault Localization ◽  
Test Case ◽  
Two Dimensional ◽  
Intelligent Software ◽  
Localization Model ◽  
Software Fault ◽  
Program Spectrum

The existing Software Fault Localization Frameworks (SFLF) based on program spectrum for estimation of statement suspiciousness have the problems that the feature type of the spectrum is single and the efficiency and precision of fault localization need to be improved. To solve these problems, a framework 2DSFLF proposed in this paper and used to evaluate the effectiveness of software fault localization techniques (SFL) in two-dimensional eigenvalues takes both dynamic and static features into account to construct the two-dimensional eigenvalues statement spectrum (2DSS). Firstly the statement dependency and test case coverage are extracted by the feature extraction of 2DSFLF. Subsequently these extracted features can be used to construct the statement spectrum and data flow spectrum which can be combined into the optimized spectrum 2DSS. Finally an estimator which takes Radial Basis Function (RBF) neural network and ridge regression as fault localization model is trained by 2DSS to predict the suspiciousness of statements to be faulty. Experiments on Siemens Suit show that 2DSFLF improves the efficiency and precision of software fault localization compared with existing techniques like BPNN, PPDG, Tarantula and so fourth.

scholarly journals Impact of initial conditions on the prediction of the spread of thermal pollution in rivers

2018 ◽  
Vol 40 ◽  
pp. 05048
Author(s):  
Monika B. Kalinowska ◽  
Pawel M. Rowiński ◽  
Artur Magnuszewski
Keyword(s):  
Open Channel ◽  
Flow Model ◽  
River Flow ◽  
Initial Conditions ◽  
Two Dimensional ◽  
River Temperature ◽  
Heated Water ◽  
Different Temperatures ◽  
Rivmix Model ◽  
Water Depths

The influence of initial conditions on the prediction of the increase of river temperature below the point of release of heated water for a designed power plant has been analysed in this study. The results for different assumed values of river flow and different temperatures of the discharged heated water have been presented. The results have been analysed taking into account existing legal frames. The two-dimensional inhouse RivMix model has been used to simulate the temperature distribution whereas the two-dimensional depth-averaged turbulent open channel flow model CCHE2D has been used to simulate the velocity fields and the water depths for the selected flows of the river.

Lagrangian approach to time-dependent laminar dispersion in rectangular conduits. Part 1. Two-dimensional flows

1988 ◽  
Vol 190 ◽  
pp. 201-215 ◽  
Author(s):  
Shimon Haber ◽  
Roberto Mauri
Keyword(s):  
Channel Flow ◽  
Poiseuille Flow ◽  
Open Channel ◽  
Molecular Diffusion ◽  
Dispersion Coefficient ◽  
Brownian Particle ◽  
Open Channel Flow ◽  
Taylor Dispersion ◽  
Time Dependent ◽  
Two Dimensional

Time-dependent mean velocities and dispersion coefficients are evaluated for a general two-dimensional laminar flow. A Lagrangian method is adopted by which a Brownian particle is traced in an artificially restructured velocity field. Asymptotic expressions for short, medium and long periods of time are obtained for Couette flow, plane Poiseuille flow and open-channel flow over an inclined flat surface. A new formula is suggested by which the Taylor dispersion coefficient can be evaluated from purely kinematical considerations. Within an error of less than one percent, over the entire time domain and for various flow fields, a very simple analytical expression is derived for the time-dependent dispersion coefficient \[ \tilde{D}(\tau) = D + D^T\left(1-\frac{1-{\rm e}^{-\alpha\tau}}{a\tau}\right), \] where D is the molecular diffusion coefficient, DT denotes the Taylor dispersion coefficient, τ stands for the non-dimensional time π2Dt/Y/, Y is the distance between walls and a = (N + 1)2 is an integer which is determined by the number of symmetry planes N that the flow field possesses. For Couette and open-channel flow there are no planes of symmetry and a = 1; for Poiseuille flow there is one plane of symmetry and a = 4.

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