Ability of Preissmann slot scheme to simulate smooth pressurisation transient in sewers

2010 ◽  
Vol 62 (8) ◽  
pp. 1848-1858 ◽  
Author(s):  
Giovanni Battista Ferreri ◽  
Gabriele Freni ◽  
Pietro Tomaselli
Keyword(s):  
Open Source Software ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Rainfall Events ◽  
Storm Water Management Model ◽  
Practical Applications ◽  
Software Products ◽  
Drainage Networks ◽  
Software Product ◽  
Heavy Rainfall Events

Urban drainage networks are generally designed to operate in a free-surface flow condition. However, as a consequence of heavy rainfall events or network malfunctions, the filling of sewers (pressurisation) and network overflow may occur. Several modelling software products are commonly used to simulate floods in drainage networks, and their results are usually thought to be reliable and robust. However, no specific studies have been carried out on the behaviour of these modelling products during the pressurisation transition. Mathematical models often use the Preissmann slot concept to handle pressurisation. In this paper, on the basis of laboratory pipe tests, the reliability of such a scheme is studied by means of a popular and open-source software product: SWMM (Storm Water Management Model). Many numerical tests were carried out with SWMM, varying the spatial and time steps and the Preissmann slot width, in order to examine the performance of the modelling software over intervals of these parameters even wider than what is usual in practical applications. The comparison between simulated and experimental surges allows one to draw interesting conclusions regarding the effectiveness of software products analogous to SWMM in simulating pressurisation, as well as the choice of the parameters themselves.

scholarly journals Experimental study on the hydraulic capacity of grate inlets with supercritical surface flow conditions

2019 ◽  
Vol 79 (9) ◽  
pp. 1717-1726 ◽  
Author(s):  
Svenja Kemper ◽  
Andreas Schlenkhoff
Keyword(s):  
Numerical Models ◽  
Surface Flow ◽  
Physical Model Test ◽  
Geometrical Parameters ◽  
Flow Conditions ◽  
Rainfall Events ◽  
Real Flow ◽  
Underground System ◽  
Heavy Rainfall Events ◽  
Good Agreement

Abstract Due to an increasing number of heavy rainfall events, the managing of urban flooding requires new design approaches in urban drainage engineering. With bidirectional coupled numerical models the surface runoff, the underground sewer flow and the interaction processes between both systems can be calculated. Most of the numerical models use a weir equation to calculate the surface to sewer flow with unsurcharged flow conditions, but uncertainties still exist in the representation of the real flow conditions. Street inlets, existing in different types, are the connecting elements between the surface and the underground system. In the present study, an empirical formula was developed based on physical model test runs to estimate the hydraulic capacity and type-specific efficiency of grate inlets with supercritical surface flow. Influencing hydraulic parameters are water depth and flow velocity upstream of the grate and, in addition, different geometrical parameters are taken into account, such as the grate dimensions or the orientation of the bars (transverse, longitudinal or diagonal). Good agreement between estimated and measured results could be proven with relative deviations less than 1%.

Explicit Approximations for Calculating Potential Flow About a Body

1983 ◽  
Vol 27 (01) ◽  
pp. 1-12
Author(s):  
F. Noblesse ◽  
G. Triantafyllou
Keyword(s):  
Free Surface ◽  
Potential Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Wave Resistance ◽  
Two Dimensional ◽  
Regular Waves ◽  
Practical Applications ◽  
Flow Problems ◽  
Unbounded Fluid

Several explicit approximations for calculating nonlifting potential flow about a body in an unbounded fluid are studied. These approximations are shown to be exact in the particular cases of flows due to translations of ellipsoids, and they are compared with the exact potential for two-dimensional flows about ogives in translatory motions. Two approximations, given by formulas (31) and (32) in the conclusion, appear to be of particular interest for practical applications, and they can be extended to free-surface flow problems, for example, ship wave resistance, and radiation and diffraction of regular waves by a body.

scholarly journals Evolution of karst conduit networks in transition from pressurised flow to free surface flow

2014 ◽  
Vol 11 (6) ◽  
pp. 6519-6559
Author(s):  
M. Perne ◽  
M. D. Covington ◽  
F. Gabrovšek
Keyword(s):  
Free Surface ◽  
Free Surface Flow ◽  
Initial Distribution ◽  
Surface Flow ◽  
Deep Penetration ◽  
Adjacent Area ◽  
Time Step ◽  
Storm Water Management Model ◽  
Conduit Networks ◽  
Stable Flow

Abstract. We present a novel modelling approach to study the evolution of conduit networks in soluble rocks. Unlike the models presented so far, the model allows a transition from pressurised (pipe) flow to a free surface (open channel) flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolutional enlargement within each time step and steps through time until a stable flow pattern establishes. The flow in each time step is calculated by calling the EPA Storm Water Management Model (EPA SWMM), which efficiently solves the 1-D Saint Venant equations in a network of conduits. We present several cases with low dip and sub-vertical networks to demonstrate mechanisms of flow pathway selection. In low dip models the inputs were randomly distributed to several junctions. The evolution of pathways progresses upstream: initially pathways linking outlets to the closest inputs evolve fastest because the gradient along these pathways is largest. When a pathway efficiently drains the available recharge, the head drop along the pathway attracts flow from the neighbouring upstream junctions and new connecting pathways evolve. The mechanism progresses from the output boundary inwards until all inputs are connected to the stable flow system. In the pressurised phase, each junction is drained by at least one conduit, but only one conduit remains active in the vadose phase. The selection depends on the initial geometry of a junction, initial distribution of diameters, the evolution in a pressurised regime, and on the dip of the conduits, which plays an important role in vadose entrenchment. In high dip networks, the vadose zone propagates downwards and inwards from the rim of the massif. When a network with randomly distributed initial diameters is supplied with concentrated recharge from the adjacent area, the sink point regresses up upstream along junctions connected to the prominent pathways. Large conductive structures provide deep penetration of high hydraulic head and give rise to high gradients and possible fast evolution of conduit systems deep within the massif.

scholarly journals Role of Open Source Software in Modern Development of Enterprise Information Systems

2021 ◽  
Vol 21 (2) ◽  
pp. 16-22
Author(s):  
A.A. Shinkarev ◽  
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Source Code ◽  
Enterprise Information ◽  
Enterprise Information Systems ◽  
Software Products ◽  
Modern Development ◽  
Software Product ◽  
The Moment ◽  
Product Package

At the moment there are many open source software products and packages, and their number is increasing every day. So it can be concluded that publishing source code is becoming more and more popular in the world of software development. When publishing the source code of a software solution or software package for use in the developer community, special attention should be given to the license type – this affects which scenarios will be available for use of the published package or software solution. It is also necessary to draw up full and detailed documentation and decide on the ways to promote the published package among developers. The purpose of the study was to justify the feasibility and necessity of publishing software products, packages and libraries for their use by other developers to build their own systems and services. The author meant to describe the major open source licenses, identify their features and differences, and those situations for which this or that type of license is suitable, as well as to demonstrate the need of writing documentation and describe ways to promote and popularize published software products, packages, and libraries in the developer community. Materials and methods. The paper considers official license documents describing conditions of use, reproduction, and distribution. The author analyzes the main ways and means to promote open source software products. Results. The article substantiates the relevance of publishing and using the source code of a software product, package or library. The author describes the main provisions of the most common licenses and gives advice on choosing the type of license when publishing source code for free use. The necessity of writing documentation for the published software product is substantiated. The article also describes some of the ways to promote published packages, such as the choice of name, speaking at conferences, and publishing articles with case studies.

Difference Formulation and Slope Invariance in Spatially Varied Free Surface Flow

Volume 1 ◽  
2004 ◽  
Author(s):  
S. David Graber
Keyword(s):  
Free Surface ◽  
Pipe Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Reference Source ◽  
Practical Applications ◽  
Physical Reasoning ◽  
Difference Form ◽  
The Difference ◽  
The Relationship

The relationship for combined increasing and decreasing free surface flow is presented in difference form, and then particularized to spatially increasing and spatially decreasing flows. For spatially decreasing flow, a theoretical difference is noted between the writer’s version and that in a widely-used reference source. By investigating an application for uniformly decreasing, full-pipe flow, it is shown by physical reasoning and comparison of an available analytical solution to the alternate versions of the difference relationship that the writer’s difference relationship is the correct one. Free surface spatially varied flow relationships are specialized to pressure conduits to demonstrate conditions of slope invariance, which has important and somewhat counter-intuitive ramifications for certain practical applications encountered in environmental engineering.

Discharge and flow field of the circular channel along the side weir

2015 ◽  
Vol 42 (4) ◽  
pp. 273-280 ◽  
Author(s):  
Hamed Azimi ◽  
Hazhar Hadad ◽  
Zakarya Shokati ◽  
Mohammad Sajad Salimi
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Circular Channel ◽  
Side Weir ◽  
Stream Surface ◽  
Discharge Coefficients ◽  
Drainage Networks ◽  
Surface Variation

The side weir is one of the most important hydraulic structures that is used by hydraulic engineers for adjusting and controlling flow in urban waste collection systems, irrigation and drainage networks. In this study, an equation is proposed for computing side weir discharge located on circular channels. The equation computes the side weir discharge with sufficient accuracy. Then, the RNG k–ε turbulence model is used for simulating the turbulence of the flow field and the free surface flow variations are modeled using volume of fluid scheme. Comparing experimental results with numerical simulations indicates acceptable accuracy of the numerical model. Also, the side weir discharge coefficients, flow free surface variation, behavior of dividing stream surface and variations of stagnation point height for different discharges within a circular channel along a side weir were examined.

scholarly journals Evolution of karst conduit networks in transition from pressurized flow to free-surface flow

2014 ◽  
Vol 18 (11) ◽  
pp. 4617-4633 ◽  
Author(s):  
M. Perne ◽  
M. Covington ◽  
F. Gabrovšek
Keyword(s):  
Free Surface ◽  
Environmental Protection ◽  
Environmental Protection Agency ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Protection Agency ◽  
Time Step ◽  
Storm Water Management Model ◽  
Conduit Networks ◽  
Stable Flow

Abstract. Most of the existing models of speleogenesis are limited to situations where flow in all conduits is pressurized. The feedback between the distribution of hydraulic head and growth of new solution conduits determines the geometry of the resulting conduit network. We present a novel modeling approach that allows a transition from pressurized (pipe) flow to a free-surface (open-channel) flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolution enlargement within each time step and steps through time until a stable flow pattern is established. The flow in each time step is calculated by calling the US Environmental Protection Agency Storm Water Management Model (US Environmental Protection Agency, 2014), which efficiently solves the 1-D Saint-Venant equations in a network of conduits. Two basic scenarios are modeled, a low-dip scenario and a high-dip scenario. In the low-dip scenario a slightly inclined plane is populated with a rectangular grid of solution conduits. The recharge is distributed to randomly selected junctions. The results for the pressurized flow regime resemble those of the existing models. When the network becomes vadose, a stable flow pathway develops along a system of conduits that occupy the lowest positions at their inlet junctions. This depends on the initial diameter and inlet position of a conduit, its total incision in a pressurized regime and its alignment relative to the dip of the plane, which plays important role during the vadose entrenchment. In the high-dip scenario a sub-vertical network with recharge on the top and outflow on the side is modeled. It is used to demonstrate the vertical development of karst due to drawdown of the water table, development of invasion vadose caves during vadose flow diversion and to demonstrate the potential importance of deeply penetrating conductive structures.

Digital education: Using electronic resources in psychological support of the educational process

2020 ◽  
pp. 55-61
Author(s):  
Ju. A. Tikhonova
Keyword(s):  
Preschool Education ◽  
Educational Process ◽  
Psychological Support ◽  
Diagnostic Methods ◽  
Practical Application ◽  
Software Products ◽  
School Year ◽  
Psychological Service ◽  
Software Product ◽  
The City

The article discusses the development trends of the modern preschool education system in the aspect of the activity of the teacherpsychologist of the preschool educational organization. The experience of using 1C software products in the practical work of the psychological service of kindergarten 318 of the city of Perm in the aspects of psychological monitoring of children’s readiness to study at school and correctional and developmental work with preschool children is presented. The components of the child’s psychological readiness for school are described. On practical examples, diagnostic methods for determining the level of readiness of children for schooling are analyzed. The data of testing kindergarten pupils at the beginning of the 2019/2020 school year on the parameters allowing to identify urgent problems and determine the direction of the necessary correctional development work are presented. Features of the practical application of the software product 1C:Preschool Psychodiagnostics in the process of psychological support of preparing children for school are considered. Methods are described, the scope of which is aimed not only at the study of personality traits, but also at its development. The possibilities of using games of the 1C:Educational Collection in the correctional and developmental work are disclosed. The description of game collections is given, options for their use are presented.

Analysing Mechanical Systems in Domestic and Foreign CAD Systems

2018 ◽  
pp. 10-17
Author(s):  
V. A. Martynyuk ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk
Keyword(s):  
Sheet Material ◽  
The Finite Element Method ◽  
Cad Systems ◽  
Cad System ◽  
Software Products ◽  
Foreign Products ◽  
Nonlinear Algebraic Systems ◽  
Software Product ◽  
Pipeline Design ◽  
The Mathematical Model

The article considers applications of foreign CAD-systems in creating the challenging projects at domestic enterprises and design bureaus. As stated in the article "... presently, there is no domestic CAD-system that could completely replace such foreign products as NX, CATIA, Credo". Besides, due to international cooperation in creating the challenging projects (for example, the project to create a modern wide-body aircraft, proposed jointly with China), it makes sense to use the worldwide known and popular CAD systems (the aforementioned NX, CATIA, Credo). Therefore, in the foreseeable future, we will still have to use foreign software products. Of course, there always remains a question of the reliability of the results obtained. Actually, this question is always open regardless of what software product is used - domestic or foreign. This question has been haunting both developers and users of CAD systems for the last 30 to 40 years. But with using domestic systems, it is much easier to identify the cause of inaccurate results and correct the mathematical models used, the methods of numerical integration applied, and the solution of systems of nonlinear algebraic systems. Everything is much more complicated if we use a foreign software product. All advertising conversations that there is a tool to make the detected errors available to the developers, remain only conversations in the real world. It is easily understandable to domestic users, and, especially, to domestic developers of similar software products. The existing development rates and competition for potential buyers dictate a rigid framework of deadlines for releasing all new versions of the product and introducing the latest developments into commercial product, etc. As a result, the known errors migrate from version to version, and many users have accepted it long ago. Especially, this concerns the less popular tools rather than the most popular applications (modules) of a CAD system. For example, in CAD systems, the "Modeling" module where geometric models of designed parts and assembly units are created has been repeatedly crosschecked. But most of the errors are hidden in applications related to the design of parts from sheet material and to the pipeline design, as well as in applications related to the analysis of moving mechanisms and to the strength or gas dynamic analysis by the finite element method.The article gives a concrete example of a moving mechanism in the analysis of which an error was detected using the mathematical model of external influence (a source of speed) in the NX 10.0 system of Siemens.

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