scholarly journals Numerical Study of the Process of Salt Water Inflow to the Don Mouth from the Taganrog Bay

2021 ◽  
Vol 28 (2) ◽  
Author(s):  
А. L. Chikin ◽  
L. G. Chikina ◽  
◽  
Keyword(s):  
Numerical Study ◽  
Salt Water ◽  
Finite Difference Methods ◽  
Main Channel ◽  
Water Inflow ◽  
Saint Venant Equations ◽  
Complex Mathematical Model ◽  
Surge Phenomena ◽  
Salt Distribution ◽  
Taganrog Bay

Purpose. Numerical study based on the model example is aimed at examining the process of the salt water inflow to the Stary Don sleeve from the Taganrog Bay due to the wind water surge. Methods and Results. Complex mathematical model of the flow and salt distribution in the open riverbed is described. The section of the River Don, consisting of the Stary Don sleeve and a part of the main channel was considered. Salt is delivered through the host reservoir – the Taganrog Bay. The model is described by the system of Saint-Venant equations and the convection-diffusion equation. The problem is solved by the finite-difference methods. The results of the numerically studied influence of the sea surface level in the Taganrog Bay both on the flow nature in the Don Delta area and the degree of salt penetration upstream of the river are obtained. It was numerically established that the flow rate did not significantly affect salt concentration in the Don main channel. Conclusions. The computational experiments showed that the decisive factor in the process of the salt water inflow to the Don Delta from the Taganrog Bay consisted in the sea level significant increase resulting from extreme wind surges; and the preceding runoffs enhanced this effect even greater. The represented model gives an idea of the general trend in the process of the Don Delta possible salinization as a result of the surge phenomena.

scholarly journals Numerical Study of the Process of Salt Water Inflow to the Don Mouth from the Taganrog Bay

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
А. L. Chikin ◽  
L. G. Chikina ◽  
◽  
Keyword(s):  
Numerical Study ◽  
Salt Water ◽  
Finite Difference Methods ◽  
Main Channel ◽  
Water Inflow ◽  
Saint Venant Equations ◽  
Complex Mathematical Model ◽  
Surge Phenomena ◽  
Salt Distribution ◽  
Taganrog Bay

Purpose. Numerical study based on the model example is aimed at examining the process of the salt water inflow to the Stary Don sleeve from the Taganrog Bay due to the wind water surge. Methods and Results. Complex mathematical model of the flow and salt distribution in the open riverbed is described. The section of the River Don, consisting of the Stary Don sleeve and a part of the main channel was considered. Salt is delivered through the host reservoir – the Taganrog Bay. The model is described by the system of Saint-Venant equations and the convection-diffusion equation. The problem is solved by the finite-difference methods. The results of the numerically studied influence of the sea surface level in the Taganrog Bay both on the flow nature in the Don Delta area and the degree of salt penetration upstream of the river are obtained. It was numerically established that the flow rate did not significantly affect salt concentration in the Don main channel. Conclusions. The computational experiments showed that the decisive factor in the process of the salt water inflow to the Don Delta from the Taganrog Bay consisted in the sea level significant increase resulting from extreme wind surges; and the preceding runoffs enhanced this effect even greater. The represented model gives an idea of the general trend in the process of the Don Delta possible salinization as a result of the surge phenomena

scholarly journals MODELLING THE PROCESS OF SALTWATER PENETRATION FROM THE TAGANROG BAY AT THE MOUTH OF THE DON

2020 ◽  
Vol 1 (5) ◽  
pp. 97-100
Author(s):  
A.L. Chikin ◽  
◽  
L.G. Chikina ◽  
Keyword(s):  
Numerical Study ◽  
Saline Water ◽  
Finite Difference Methods ◽  
Extreme Wind ◽  
Saint Venant Equations ◽  
Don River ◽  
Complex Mathematical Model ◽  
Surge Phenomena ◽  
Host Reservoir ◽  
Taganrog Bay

The description of a complex mathematical model of the flow and distribution of salt in an open riverbed is given. We consider the channel of the Don River, consisting of the Stary Don and the main channel. Salt is delivered through the host reservoir, the Taganrog Bay. The model is described by the system of Saint-Venant equations and the convectiondiffusion equation. The problem is solved by finite-difference methods. The results of a numerical study of the influence of the water surface level in the Taganrog Bay on the nature of the flow in the delta part of the Don, as well as on the degree of salt penetration upstream of the river, are obtained. It has been numerically established that the flow rate does not significantly affect the salt concentration in the main Don channel. Computational experiments have shown that the decisive factor in the supply of saline water from the Taganrog Bay to the Don Delta is a significant increase in the water level due to extreme wind surges, and the preceding runoffs further enhance this effect. The presented model gives an idea of the general trend in the development of the process of possible salinization of the Don Delta with surge phenomena.

Assessing flood risk and detecting changes of salt water inflow in a coastal micro-tidal brackish marsh using GIS

2008 ◽  
Vol 37 (3) ◽  
Author(s):  
Jacek Urbański ◽  
Agata Ślimak
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Flood Risk ◽  
Salt Water ◽  
Brackish Marsh ◽  
Distance Functions ◽  
Water Inflow ◽  
Small Range ◽  
Natural Environments ◽  
Baltic Coast

Assessing flood risk and detecting changes of salt water inflow in a coastal micro-tidal brackish marsh using GISIn order to assess changes in salt water inflow and potential flood risks due to sea level rise in a micro-tidal Beka brackish marsh on the Polish Baltic Coast GIS was used. Such wetlands are important elements of coastal zone natural environments. Creating a geodatabase within a GIS system makes it possible to carry out broad analyses of complex systems, such as coastal wetlands. The results indicate that a 40 cm sea-level rise would considerably increase the frequency of flooding in the investigated area, in part because of the small range of the annual sea level oscillations there. A map of the index of changes in saltwater inflow, created with the help of cost-weighted distance (functions), shows that changes which have occurred along the shore, consisting of filling in the drainage channel outlets, have likely had a significant impact on the vegetation of the area.

scholarly journals Experimental and Numerical Study on Water Filling and Air Expelling Process in a Pipe with Multiple Air Valves under Water Slow Filling Condition

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2511
Author(s):  
Jintao Liu ◽  
Di Xu ◽  
Shaohui Zhang ◽  
Meijian Bai
Keyword(s):  
Numerical Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Practical Method ◽  
Navier Stokes ◽  
Physical Processes ◽  
Two Phase ◽  
Saint Venant Equations ◽  
Water Filling ◽  
Air Valve

This paper investigates the physical processes involved in the water filling and air expelling process of a pipe with multiple air valves under water slow filling condition, and develops a fully coupledwater–air two-phase stratified numerical model for simulating the process. In this model, the Saint-Venant equations and the Vertical Average Navier–Stokes equations (VANS) are respectively applied to describe the water and air in pipe, and the air valve model is introduced into the VANS equations of air as the source term. The finite-volume method and implicit dual time-stepping method (IDTS) with two-order accuracy are simultaneously used to solve this numerical model to realize the full coupling between water and air movement. Then, the model is validated by using the experimental data of the pressure evolution in pipe and the air velocity evolution of air valves, which respectively characterize the water filling and air expelling process. The results show that the model performs well in capturing the physical processes, and a reasonable agreement is obtained between numerical and experimental results. This agreement demonstrates that the proposed model in this paper offers a practical method for simulating water filling and air expelling process in a pipe with multiple air valves under water slow filling condition.

Numerical Study on the Growth and Collapse of a Cavitation Bubble inside a Rigid Cylinder with a Compliant Coating

2014 ◽  
Vol 875-877 ◽  
pp. 1194-1198
Author(s):  
Fardin Rouzbahani ◽  
M.T. Shervani-Tabar
Keyword(s):  
Integral Equation ◽  
Boundary Integral Equation ◽  
Cavitation Bubble ◽  
Numerical Study ◽  
Finite Difference Methods ◽  
Life Time ◽  
Integral Equation Method ◽  
Boundary Integral ◽  
Compliant Coating ◽  
Rigid Cylinder

In this paper, growth and collapse of a cavitation bubble inside a rigid cylinder with a compliant coating (a model of humans vessels) is studied using Boundary Integral Equation and Finite Difference Methods. The fluid flow is treated as a potential flow and Boundary Integral Equation Method is used to solve Laplaces equation for velocity potential. The compliant coating is modeled as a membrane with a spring foundation. The effects of the parameters describing the flow and the parameters describing the compliant coating on the interaction between the fluid and the cylindrical compliant coating are shown throughout the numerical results. It is shown that by increasing the compliancy of the coating, the bubble life time is decreased and the mass per unit area has an important role in bubble behavior.

scholarly journals Calibration of Manning’s roughness in non-instrumented rural basins using a distributed hydrological model

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 164-173
Author(s):  
Carlos Andrés Caro Camargo ◽  
Oscar Fabián Pacheco Merchán ◽  
Hans Paul Sánchez Tueros
Keyword(s):  
Hydrological Model ◽  
Numerical Study ◽  
Research Work ◽  
Roughness Coefficient ◽  
Distributed Hydrological Model ◽  
The Standard Model ◽  
Saint Venant Equations ◽  
Volume Method ◽  
Best Fit ◽  
Selection Of

The purpose of this research work was to calibrate the Manning's roughness coefficient in rural non-instrumented basins using a distributed hydrological model. The process consisted of the selection of several basins with vegetal cover of forests and grasslands, and its subsequent experimental numerical study, in which the hydrological response hydrograph of each reference basin was obtained from the HEC-HMS software and the hydrograph to be calibrated was the Iber software, which is a hydrodynamic model based on the two-dimensional Saint Venant equations, solved by the finite volume method. Once the calibration process was carried out, the roughness coefficients with the best fit for each basin were identified with increases in precipitation, identifying the limitations of these values and the standard model used.

scholarly journals Numerical study of the physical processes of gas leakage in the compression ring in diesel engines

2021 ◽  
Vol 2118 (1) ◽  
pp. 012016
Author(s):  
J A Pabón León ◽  
J P Rojas Suárez ◽  
M S Orjuela Abril
Keyword(s):  
Numerical Model ◽  
Internal Combustion Engines ◽  
Numerical Study ◽  
Cylinder Liner ◽  
Combustion Engines ◽  
Combustion Gases ◽  
Gas Leakage ◽  
Lubrication Film ◽  
Compression Ring ◽  
Complex Mathematical Model

Abstract In this research, the construction of a numerical model is proposed for the analysis of the friction processes and the thickness of the lubrication film present in the compression ring of internal combustion engines. The model is built using MATLAB software, and three load conditions are used as reference (2 Nm, 4 Nm, and 6 Nm) with a rotation speed of 3600 rpm, which correspond to a stationary single-cylinder diesel engine. Comparison between model estimates and experimental results show that the development model could predict the actual engine conditions. The deviation between the numerical model and the experimental data was 17%. It was shown that the increase in engine load causes a 16% increase in the friction force of the compression ring, which implies a 50% increase in power loss due to friction processes. In general, the model developed allows the analysis of the friction processes in the compression ring and its effect on the lubrication film, considering the leakage of the combustion gases. In this way, the construction of a more complex mathematical model is achieved, which allows improving the precision in the analyzes related to the interaction between the compression ring and the cylinder liner.

scholarly journals NUMERICAL STUDY OF CURRENTS IN TSIMLYANSK RESERVOIR AT DIFFERENT LEVELS OF RESERVOIR FILLING

2020 ◽  
Vol 2 (5) ◽  
pp. 33-36
Author(s):  
A.V. Kleshchenkov ◽  
◽  
A.L Chikin ◽  
L.G Chikina ◽  
◽  
...  
Keyword(s):  
Shallow Water ◽  
Numerical Study ◽  
Equations Of Motion ◽  
Finite Difference Methods ◽  
Field Work ◽  
Surface Currents ◽  
Tsimlyansk Reservoir ◽  
Dam Site ◽  
Reservoir Filling ◽  
Different Levels

A description of the mathematical model of the hydrodynamics of the Tsimlyansk reservoir is given. In shallow water regions, the flows are described by the equations of shallow water, and in deep-water regions by both the equations of shallow water and the three-dimensional equations of motion of an incompressible viscous fluid. The problem is solved by finite difference methods on a uniform difference grid. The calculations were carried out at different levels of reservoir filling. A comparison of the results obtained with the surface currents scheme constructed based on the results of field work performed in the spring of 2019 is carried out. The pictures of currents were obtained at different water edges. For the period of expeditionary field work in May 2019, hydrodynamics was calculated on the near-dam site using wind data obtained for this period and compared with the results of field measurements of currents. Comparison of the obtained results of numerical modeling with the scheme of surface currents measured from the research vessel reveals a high proportion of convergence of the calculated and field data. The obtained estimates of the modeling results allow us to proceed to the problem of predicting unfavorable hydrometeorological conditions in the Tsimlyansk reservoir, which carry the risk of disrupting the operation of the water intakes of Volgodonsk located in the southern part of the near-dam site

CFD ANALYSIS OF FLOW THROUGH HORIZONTAL CEILING OPENING DUE TO BUOYANCY AND PRESSURE DIFFERENCE

2013 ◽  
Vol 25 (01) ◽  
pp. 1340022 ◽  
Author(s):  
B. GERA ◽  
P. K. SHARMA ◽  
R. K. SINGH
Keyword(s):  
Critical Pressure ◽  
Numerical Study ◽  
Salt Water ◽  
Density Difference ◽  
Exchange Flow ◽  
Navier Stokes Equation ◽  
Directional Flow ◽  
Flow Through ◽  
Horizontal Vent ◽  
Lower Compartment

The buoyancy driven exchange flow through the large openings in horizontal partitions occurs in many practical situations such as in enclosed regions with a ceiling opening and a heat source such as fire. The density difference between two compartments arises partly due to difference in composition and partly from the difference in temperature. A heavier fluid located on the top of a lighter fluid and separated by a horizontal vent constitutes a gravitationally unstable system. Horizontal vents produce flow, which are unstable with irregular oscillatory behavior. However, when lower compartment is slightly pressurized the flow becomes stable and unidirectional. A numerical study has been performed to characterize the bi-directional flow and transition to unidirectional flow through a horizontal vent in an enclosure, due to differences in pressure and density across the vent. Fresh and salt water has been considered as working fluids to create density difference across the vent with a pressure field imposed in the lower compartment. The pressure in the lower region was increased to find the critical pressure corresponding to transition to unidirectional from bi-directional flow. Unsteady, 2D axisymmetric, incompressible Navier–Stokes equation along with species, turbulence and continuity equation have been solved with finite volume method using the in-house computational fluid dynamics (CFD) code. Several cases were examined to compute the critical pressure for various density differences for low opening aspect ratio. The code has been validated with reported experiments and used to simulate various other practical cases occurred during fire induced flow through such openings.

Numerical Study of Some Three-Dimensional Laminar Free Convective Flows

1976 ◽  
Vol 98 (4) ◽  
pp. 570-575 ◽  
Author(s):  
P. H. Oosthuizen
Keyword(s):  
Numerical Study ◽  
Finite Difference Methods ◽  
Three Dimensional ◽  
The Body ◽  
Three Dimensional Flow ◽  
Constant Property ◽  
Convective Flows ◽  
Boundary Layer Equations ◽  
Dimensional Flow ◽  
Acceleration Component

Three-dimensional buoyancy-induced flows over plates and cylinders have been considered. The three-dimensional flow results either from the fact that the body is inclined to the horizontal or from the fact that there is a longitudinal acceleration component. Both the cases where this acceleration component is constant and the case where it varies linearly with the distance along the body have been considered. The study is based on the use of the constant-property boundary-layer equations. These equations have been rewritten in terms of dimensionless variables, and thus the resulting equations do not explicitly depend on the nature of mechanism causing the three-dimensional flow. These equations have been solved numerically using finite-difference methods, with heat-transfer distributions for various representative situations being deduced.

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