A 2D Numerical Model for Simulation of Two-Dimensional Circular Dam-Break

2011 ◽  
Vol 130-134 ◽  
pp. 2993-2996
Author(s):  
Ming Qin Liu ◽  
Y.L. Liu
Keyword(s):  
Solution Procedure ◽  
Dam Break ◽  
Curvilinear Coordinates ◽  
Two Dimensional ◽  
Proposed Model ◽  
Curvilinear Coordinate ◽  
Orthogonal Curvilinear Coordinate System ◽  
Orthogonal Curvilinear Coordinates ◽  
Averaged Model ◽  
The Mathematical Model

The purpose of this paper is to present a 2D depth-averaged model under orthogonal curvilinear coordinates for simulating two-dimensional circular dam-break flows. The proposed model uses an orthogonal curvilinear coordinate system efficiently and accurately to simulate the flow field with irregular boundaries. As for the numerical solution procedure, The SIMPLEC solution procedure has been used for the transformed governing equations in the transformed domain. Practical application of the model is illustrated by an example, which demonstrates that the mathematical model can capture hydraulic discontinuities accurately such as steep fronts, hydraulic jump and drop, etc.

A Calculation Procedure for Three-Dimensional, Viscous, Compressible Duct Flow. Part I—Inviscid Flow Considerations

1979 ◽  
Vol 101 (4) ◽  
pp. 415-422 ◽  
Author(s):  
John Moore ◽  
Joan G. Moore
Keyword(s):  
Three Dimensional ◽  
Inviscid Flow ◽  
Solution Procedure ◽  
Curvilinear Coordinates ◽  
Two Dimensional ◽  
Duct Flow ◽  
Conservation Equations ◽  
Two Dimensional Flow ◽  
Flow Part ◽  
Orthogonal Curvilinear Coordinates

A method for computing three-dimensional duct flows is described. The procedure involves iteration between a marching integration of the conservation equations through the flow field and the solution of an elliptic pressure-correction equation. The conservation equations are written in orthogonal curvilinear coordinates. The solution procedure is illustrated by calculations of two-dimensional flow in an accelerating rectangular elbow with 90 deg of turning. An approach to calculating three-dimensional viscous flow, starting with the solution for two-dimensional inviscid flow is suggested. This approach is used in Part II which starts with the results of the present two-dimensional “inviscid” flow calculations.

scholarly journals Application of the 2D Depth-Averaged Model, FLATModel, to Pumiceous Debris Flows in the Amalfi Coast

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1159 ◽  
Author(s):  
Maria Papa ◽  
Luca Sarno ◽  
Francesco Vitiello ◽  
Vicente Medina
Keyword(s):  
Debris Flows ◽  
Initial Conditions ◽  
Morphological Evolution ◽  
Cost Effective ◽  
Integrated Approach ◽  
Dam Break ◽  
Curvilinear Coordinates ◽  
Numerical Code ◽  
Water Model ◽  
Averaged Model

Few studies about modelling pumice debris flows are available in literature. An integrated approach based on field surveys and numerical modelling is here proposed. A pumiceous debris flow, which occurred in the Amalfi Coast (Italy), is reconstructed by the numerical code, FLATModel, consisting of a two-dimensional shallow-water model written in curvilinear coordinates. The morphological evolution of the gully and of the alluvial fan was monitored by terrestrial laser scanner and photo-modelling aerial surveys, providing, in a cost-effective way, data otherwise unavailable, for the implementation, calibration and validation of the model. The most suitable resistance law is identified to be the Voellmy model, which is found capable of correctly describing the friction-collisional resistance mechanisms of pumiceous debris flows. The initial conditions of the numerical simulations are assumed to be of dam-break type: i.e., they are given by the sudden release of masses of pumice, whose shape and depths are obtained by reconstruction of the pre-event slopes. The predicted depths and shape of deposits are compared with the measured ones, where a good agreement (average error smaller than 10 cm) is observed for several dam-break scenarios. The proposed cost-effective integrated approach can be straightforwardly employed for the description of other debris flows of the same kind and for better designing risk mitigation measures.

Designing differential service strategy for two-dimensional warranty based on warranty claim data under consumer-side modularisation

2019 ◽  
Vol 234 (3) ◽  
pp. 550-561
Author(s):  
Tong Peng ◽  
Liu Chunling
Keyword(s):  
Service Providers ◽  
Claim Data ◽  
Two Dimensional ◽  
Function Type ◽  
Service Strategy ◽  
Actual Usage ◽  
Proposed Model ◽  
Warranty Service ◽  
The Mathematical Model

With the development of modular manufacturing technology and diversified demand for products, the demand for differential warranty service has become increasingly prominent. This article proposes a differential service strategy for two-dimensional warranty using warranty claim data under consumer-side modularisation. In contrast to previous research that optimised maintenance strategies under a given failure density function, this article obtains actual usage rate and failure density functions of main failure types by determining the function type and parameter fitting. A detailed case study of a product under a two-dimensional warranty is discussed to interpret the proposed model. Using the mathematical model proposed in this research, warranty service providers can offer consumers a differential warranty service under consumer-side modularisation.

Navier–Stokes Solution for Steady Two-Dimensional Transonic Cascade Flows

1988 ◽  
Vol 110 (3) ◽  
pp. 339-346 ◽  
Author(s):  
O. K. Kwon
Keyword(s):  
Stokes Equations ◽  
Solution Procedure ◽  
Curvilinear Coordinates ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Turbine Cascade ◽  
Navier Stokes Equations ◽  
Time Marching ◽  
Transonic Turbine ◽  
Transonic Cascade

A robust, time-marching Navier–Stokes solution procedure based on the explicit hopscotch method is presented for solution of steady, two-dimensional, transonic turbine cascade flows. The method is applied to the strong conservation form of the unsteady Navier–Stokes equations written in arbitrary curvilinear coordinates. Cascade flow solutions are obtained on an orthogonal, body-conforming “O” grid with the standard k–ε turbulence model. Computed results are presented and compared with experimental data.

Hydrodynamics in Tubes Perturbed by Curvilinear Obstructions

1984 ◽  
Vol 106 (3) ◽  
pp. 262-269 ◽  
Author(s):  
A. K. Rastogi
Keyword(s):  
Fluid Flow ◽  
Turbulent Flows ◽  
Separated Flows ◽  
Curvilinear Coordinates ◽  
Two Dimensional ◽  
Governing Equations ◽  
Curved Boundaries ◽  
Numerical Grid ◽  
Orthogonal Curvilinear Coordinates ◽  
Laminar And Turbulent Flows

A calculation procedure for two-dimensional separated flows over curved boundaries, e.g., flow in constricted tubes, is described. The method is based on the numerical solution with finite differences of the governing equations in orthogonal curvilinear coordinates. A body fitted curvilinear orthogonal numerical grid is generated first which is then employed for the solution of partial differential equations governing fluid flow. Results of calculations are presented for laminar and turbulent flows in constricted tubes. For turbulent flow calculations the k-ε turbulence model has been employed. Comparison between computed and measured values of flow quantities is also presented and is discussed in some detail. Although the present paper deals only with constricted pipes, the method developed is general and can be used without difficulty for two-dimensional flows over other curved boundaries.

Simulation of Flows Near a Groin in a Straight Open Channel with Effects of Streamline Curvature

2011 ◽  
Vol 383-390 ◽  
pp. 6669-6673
Author(s):  
Guang Cai Sun ◽  
Wen Li Wei ◽  
Y.L. Liu ◽  
Gui Wen Rong
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Satisfactory Agreement ◽  
Open Channel ◽  
Solution Procedure ◽  
Curvilinear Coordinates ◽  
Governing Equations ◽  
Local Curvature ◽  
Streamline Curvature ◽  
Orthogonal Curvilinear Coordinates

A mathematical model for predicting turbulence flows with effects of streamline curvature under orthogonal curvilinear coordinates is developed in this paper .The SIMPLEC solution procedure has been used for the transformed governing equations in the transformed domain. The flows near a groin in a straight open channel are employed to test the capability of the proposed turbulence model in capturing the effects of local curvature .The comparison between the computed results and experimental data shows a satisfactory agreement.

THE DEVELOPMENT OF THE MATHEMATICAL MODEL OF PREDICTING THE INDICATORS OF ACCREDITATION OF TECHNICAL UNIVERSITIES IN THE RUSSIAN FEDERATION

2017 ◽  
pp. 27-38
Author(s):  
Olga Mikhaylovna Tikhonova ◽  
Alexander Fedorovich Rezchikov ◽  
Vladimir Andreevich Ivashchenko ◽  
Vadim Alekseevich Kushnikov
Keyword(s):  
Mathematical Model ◽  
System Dynamics ◽  
Regression Model ◽  
Oriented Graph ◽  
Real Data ◽  
Educational Process ◽  
Proposed Model ◽  
Linear Differential ◽  
The University ◽  
The Mathematical Model

The paper presents the system of predicting the indicators of accreditation of technical universities based on J. Forrester mechanism of system dynamics. According to analysis of cause-and-effect relationships between selected variables of the system (indicators of accreditation of the university) there was built the oriented graph. The complex of mathematical models developed to control the quality of training engineers in Russian higher educational institutions is based on this graph. The article presents an algorithm for constructing a model using one of the simulated variables as an example. The model is a system of non-linear differential equations, the modelling characteristics of the educational process being determined according to the solution of this system. The proposed algorithm for calculating these indicators is based on the system dynamics model and the regression model. The mathematical model is constructed on the basis of the model of system dynamics, which is further tested for compliance with real data using the regression model. The regression model is built on the available statistical data accumulated during the period of the university's work. The proposed approach is aimed at solving complex problems of managing the educational process in universities. The structure of the proposed model repeats the structure of cause-effect relationships in the system, and also provides the person responsible for managing quality control with the ability to quickly and adequately assess the performance of the system.

scholarly journals On the Dragging Trajectory of Anchors in Clay for Merchant Ships

2021 ◽  
Vol 9 (2) ◽  
pp. 118
Author(s):  
Xinqing Zhuang ◽  
Keliang Yan ◽  
Pan Gao ◽  
Yihua Liu
Keyword(s):  
Mathematical Model ◽  
Structural Integrity ◽  
Indirect Measurement ◽  
Test System ◽  
Flow Rule ◽  
Burial Depth ◽  
Proposed Model ◽  
Depth Increase ◽  
Two Parameters ◽  
The Mathematical Model

Anchor dragging is a major threat to the structural integrity of submarine pipelines. A mathematical model in which the mechanical model of chain and the bearing model of anchor were coupled together. Based on the associated flow rule, an incremental procedure was proposed to solve the spatial state of anchor until it reaches the ultimate embedding depth. With an indirect measurement method for the anchor trajectory, a model test system was established. The mathematical model was validated against some model tests, and the effects of two parameters were studied. It was found that both the ultimate embedding depth of a dragging anchor and the distance it takes to reach the ultimate depth increase with the shank-fluke pivot angle, but decrease as the undrained shear strength of clay increases. The proposed model is supposed to be useful for the embedding depth calculation and guiding the design of the pipeline burial depth.

scholarly journals Content Dependent Representation Selection Model for Systems Based on MPEG DASH

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1843
Author(s):  
Jelena Vlaović ◽  
Snježana Rimac-Drlje ◽  
Drago Žagar
Keyword(s):  
Mathematical Model ◽  
Spatial Information ◽  
Relevant Literature ◽  
Video Quality ◽  
Similarity Index ◽  
Video Encoding ◽  
Adaptation Algorithm ◽  
Subjective Testing ◽  
Proposed Model ◽  
The Mathematical Model

A standard called MPEG Dynamic Adaptive Streaming over HTTP (MPEG DASH) ensures the interoperability between different streaming services and the highest possible video quality in changing network conditions. The solutions described in the available literature that focus on video segmentation are mostly proprietary, use a high amount of computational power, lack the methodology, model notation, information needed for reproduction, or do not consider the spatial and temporal activity of video sequences. This paper presents a new model for selecting optimal parameters and number of representations for video encoding and segmentation, based on a measure of the spatial and temporal activity of the video content. The model was developed for the H.264 encoder, using Structural Similarity Index Measure (SSIM) objective metrics as well as Spatial Information (SI) and Temporal Information (TI) as measures of video spatial and temporal activity. The methodology that we used to develop the mathematical model is also presented in detail so that it can be applied to adapt the mathematical model to another type of an encoder or a set of encoding parameters. The efficiency of the segmentation made by the proposed model was tested using the Basic Adaptation algorithm (BAA) and Segment Aware Rate Adaptation (SARA) algorithm as well as two different network scenarios. In comparison to the segmentation available in the relevant literature, the segmentation based on the proposed model obtains better SSIM values in 92% of cases and subjective testing showed that it achieves better results in 83.3% of cases.

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