scholarly journals A mathematical model of control volume uncertainty for comparison calibration in water flow metrology

2021 ◽  
Vol 18 ◽  
pp. 100106
Author(s):  
Sejong Chun
Keyword(s):  
Mathematical Model ◽  
Water Flow ◽  
Control Volume ◽  
Comparison Calibration

A Real-Time Mathematical Model for Three-Dimensional Tidal Flow and Water Quality

1991 ◽  
Vol 24 (6) ◽  
pp. 171-177 ◽  
Author(s):  
Zeng Fantang ◽  
Xu Zhencheng ◽  
Chen Xiancheng
Keyword(s):  
Mathematical Model ◽  
Water Quality ◽  
Real Time ◽  
Control Volume ◽  
Tidal Flow ◽  
Three Dimensional ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Practical Application ◽  
The Pearl River

A real-time mathematical model for three-dimensional tidal flow and water quality is presented in this paper. A control-volume-based difference method and a “power interpolation distribution” advocated by Patankar (1984) have been employed, and a concept of “separating the top-layer water” has been developed to solve the movable boundary problem. The model is unconditionally stable and convergent. Practical application of the model is illustrated by an example for the Pearl River Estuary.

scholarly journals Theoretical Modeling, Design and Simulation of an Innovative Diverting Valve Based on Coanda Effect

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 103
Author(s):  
Giancarlo Comes ◽  
Carlo Cravero
Keyword(s):  
Fluid Dynamics ◽  
Mathematical Model ◽  
Computational Fluid Dynamics ◽  
Additive Manufacturing ◽  
Water Flow ◽  
Coanda Effect ◽  
Geometrical Parameters ◽  
Convex Wall ◽  
Fluidic Device ◽  
Coandǎ Effect

The present work is focused on the study of an innovative fluidic device. It consists of a two-ways diverter valve able to elaborate an inlet water flow and divert it through one of the two outlets without moving parts but as a result of a fluctuation of pressure induced by two actuation ports, or channels. Such apparatus is named Attachment Bi-Stable Diverter (ABD) and is able to work with the effect of the fluid adhesion to a convex wall adjacent to it, this phenomenon is known as Coanda Effect; it generates the force responsible for the fluid attachment and the consequent deviation. The main purpose of this work is to develop a knowhow for the design and development of such particular device. A mathematical model for the ABD has been developed and used to find the relationships between the geometrical parameters and the operative conditions. A configuration has been designed, simulated with a computational fluid dynamics approach. A prototype has been printed with and additive manufacturing printer and tested in laboratory to check the effective working point of the device.

scholarly journals Mathematical Modeling of Pollution Transfer in Open Channel

2019 ◽  
pp. 49-50
Author(s):  
Petro Martyniuk ◽  
Oksana Ostapchuk ◽  
Vitalii Nalyvaiko
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Numerical Solution ◽  
Boundary Problem ◽  
Water Flow ◽  
Numerical Experiments ◽  
Open Channel ◽  
Computational Algorithm ◽  
The Mathematical Model

The problem of pollution transfer by water flow in open channel was considered. The mathematical model of the problem was constructed. The numerical solution of the onedimensional boundary problem was obtained. The computational algorithm for solving the problem was programmed to implement. A series of numerical experiments with their further analysis was conducted.

Mathematical Model of Multi-Layer Wall with Phase Change Material and its Use in Optimal Design

2013 ◽  
Vol 649 ◽  
pp. 295-298
Author(s):  
Lubomir Klimes ◽  
Pavel Charvát ◽  
Josef Stetina
Keyword(s):  
Mathematical Model ◽  
Optimal Design ◽  
Phase Change ◽  
Phase Change Material ◽  
Control Volume ◽  
Operational Conditions ◽  
Volume Method ◽  
The Mathematical Model ◽  
Change Material

The paper deals with the mathematical model of the multi-layer wall containing the phase change material (PCM). The model utilizes the effective heat capacity method for modeling the latent heat of phase change and the control volume method is used for the discretization of the model. The utilization of the model is then demonstrated on the problem of the optimal design of the multi-layer wall with the PCM. The TMY2 data for the city of Brno were used in simulations as operational conditions. The main attention is aimed at the determination of the optimal thickness of the PCM layer for the multi-layer wall design with various thicknesses of the masonry.

Application of MIKE21 MODEL on Flood Routing in the Lower Yellow River from Gaocun to Sunkou

2012 ◽  
Vol 238 ◽  
pp. 304-307
Author(s):  
Xiao Lei Zhang ◽  
Shao Lei Guo
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Water Flow ◽  
Yellow River ◽  
Reference Value ◽  
Flood Routing ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Flow Parameters ◽  
Boundary Treatment

The 2-D water flow mathematical model based on MIKE 21 software which reflects flood routing in the reach from Gaocun to Sunkou has been developed in this paper. Through the numerical simulation of the “96.8” typical flood, the simulating results in the condition of present topography are agreement with the measured ones. It shows that this model is basically reasonable in the selection aspects of river terrain, boundary treatment, roughness and water flow parameters, and the model has a reference value for simulating flood routing in the Lower Yellow River.

scholarly journals MODELING ATMOSPHERE COMPOSITION AND DETERMINING EXPLOSIBILITY IN A SEALED COAL MINE VOLUME

2014 ◽  
Vol 59 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Jianwei Cheng ◽  
Yi Luo
Keyword(s):  
Mathematical Model ◽  
Control Volume ◽  
Inert Gases ◽  
Mine Safety ◽  
Air Leakage ◽  
Gas Explosion ◽  
Triangle Diagram ◽  
Underground Coal Mines ◽  
Control Volume Approach ◽  
Explosion Risk

Abstract Explosions originated from or around the sealed areas in underground coal mines present a serious safety threat. The explosibility of the mine atmosphere depends on the composition of oxygen, combustible and inert gases. In additional, the composition in the inaccessible sealed areas change with time under various factors, such as gases emissions, air leakage, inert gases injected, etc. In order to improve mine safety, in this paper, a mathematical model based on the control volume approach to simulate the atmosphere compositions is developed, and the expanded Coward explosibility triangle diagram is used to assess the mine gas explosion risk. A computer program is developed to carry out the required computations and to display the results. In addition, the USBM explosibility diagram is also included in the program to serve as a double check.

Laboratory simulation of thermal erosion: possible application to pollution problems

Polar Record ◽  
1999 ◽  
Vol 35 (192) ◽  
pp. 67-72
Author(s):  
N. Makhloufi ◽  
F. Costard ◽  
J. Aguirre Puente ◽  
J. Costard ◽  
R. Posado Cano ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Water Flow ◽  
Thermal Flux ◽  
The Arctic ◽  
Laboratory Simulation ◽  
Thermal Erosion ◽  
Ablation Model

AbstractIn the Arctic, thermal erosion results from ground thawing produced by heat transfer when water is flowing upon the frozen ground. A mathematical model has been proposed to determine the efficiency of the process and the rate of thermal erosion. Considering a constant heat-transfer coefficient, the resulting thermal flux at the groundsurface produces ground thaw, and the unfrozen sediments can be removed by the water flow. A particular case of an ablation model consists of an immediate removing of sediments by a strong flow and by the action of gravity. An experimental hydraulic device was built to test the authors' theoretical ablation model, describing a fluvial thermalerosionprocess. The effect of different parameters (Reynolds number, water temperature, ground-ice temperature) on the rate of thermal erosion for samples of frozen sand was investigated. Results from the experiments are in agreement with theoretical estimates using the mathematical model. Moreover, this study shows a hierarchy of parameters in terms of efficiency of the fluvial thermal-erosion process.A discussion of the possible effects of the contaminants on the erosion rate leads the authors to propose two kinds of experiments: a contaminated frozen sample eroded by a water flow, varying in this case the thermophysical properties of the sample (density, specific heat capacity, a latent heat, and change of phase), and an experiment consisting of erosion of a frozen sample by contaminated flow. This second case is also complex due to many mechanical, hydrodynamic and thermal interactions at the ground surface. This paper reports results of thermal erosionfrom experiments with icesaturated sand. A pure ice sample is used to determine the heat-transfer coefficient.

scholarly journals Numerical simulation of the non-regular mode of cooling a high-temperature metal billet by the flow of a gas-liquid medium

2018 ◽  
Vol 224 ◽  
pp. 04003
Author(s):  
Sergey Makarov ◽  
Vyacheslav Dement’yev ◽  
Tat’yana Makhneva ◽  
Elena Makarova
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
High Temperature ◽  
Liquid Medium ◽  
Liquid Flow ◽  
Control Volume ◽  
Algebraic Equations ◽  
Linear Algebraic Equations ◽  
Gas Liquid Flow ◽  
Regular Mode

A mathematical model of heat transfer at cooling a high-temperature metal billet from structural steel by the flow of a gas-liquid medium in a vertical circular channel is presented. The model has been built with the use of the continuum mechanics approaches and the theory of heat-mass transfer. The non-regular mode of cooling is considered. The results of the numerical parametric investigations of the heat transfer at cooling a metal billet are obtained for a standard regime of thermomechanical strengthening on the basis of the mathematical model of conjugate heat transfer in a two-dimensional nonstationary formulation accounting for the symmetry of the cooling medium flow relative to the longitudinal axis of a cylinder. The control volume approach is used for solving the system of differential equations. The flow field parameters are computed by an algorithm SIMPLE. For the iterative solution of the systems of linear algebraic equations the Gauss-Seidel method with under-relaxation is used. Taking into account evaporation in the liquid, the intensity of the change of the rate of cooling the material of the metal cylindrical billet by the laminar gas-liquid flow is analyzed depending on the time of cooling and the velocity of the gas-liquid flow.

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