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    Tytuł:
    Numerical analysis of open channel steady gradually varied flow using the simplified Saint-Venant equations
    Autorzy:
    Artichowicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934022.pdf
    Data publikacji:
    2011
    Wydawca:
    Politechnika Gdańska
    Tematy:
    dynamic equation
    open-channel flow
    open-channel networks
    steady flow
    Opis:
    For one-dimensional open-channel flow modeling, the energy equation is usually used. There exist numerous approaches using the energy equation for open-channel flow computations, which resulted in the development of several very efficient methods for solving this problem applied to channel networks. However, the dynamic equation can be used for this purpose as well. This paper introduces a method for solving a system of non-linear equations by the discretization of the one-dimensional dynamic equation for open-channel networks. The results of the computations using the dynamic and energy equations were compared for an arbitrarily chosen problem. Also, the reasons for the differences between the solution of the dynamic and energy equation were investigated.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2011, 15, 3-4; 317-328
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Junction Riemann problem for shallow water equations in networks
    Autorzy:
    Elshobaki, Mohamed Abdelrehim Selim Ibrahim
    Powiązania:
    https://bibliotekanauki.pl/articles/1955288.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Gdańska
    Tematy:
    channel network
    Riemann problem
    subcritical flows
    channel junctions
    open channel flows
    Opis:
    In this paper, the Riemann solution of an extended Riemann problem in channel networks is presented. The Riemann problem at a junction network is well defined in the literature. However, it is limited to symmetric networks. Here, we extend the Riemann problem to non-symmetric networks such that neither the channel width equality nor the dischargee quality are assumed. The Riemann solution is given under subcritical flow conditions to ensurethe existence and uniqueness of the solution at the junction. Taking into account the massand energy conservation laws, the necessary conditions for the Riemann solution are drawn.The results are summarized in a theorem. The theorem is illustrated with a set of numerical examples.In order to perform a one-dimensional simulation in channel networks, the inner boundary conditions at the junction (i.e., the channel intersection point) are required. It has turned out that the classical models (i.e., the Equality, Gurram, Hsu models) that have been used to supplysuch a boundary suffer from many drawbacks.Thus, here we propose to use the Riemann solution at the junction networks to provideproper boundary conditions. Then, we compare all the junction models together. The junction models are validated against experimental results found in the literature for steady state flows.Generally, the Riemann model shows good results in matching the experimental data. In particular, the Riemann model shows the best results when the bottom discontinues at the junction. For the unsteady state flows, we perform prototype case studies to test the junction models in the channel networks, and the numerical solutions are compared with the analytical solutions. The Riemann model continues to show the best results that agree with the analytical solutions. However, the validation of the junction models in the unsteady state flows remains for future work due to the limited amount of real data.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2018, 22, 1; 9-84
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulation of laminar flow passing through a T-splitter plate and bridge pier.
    Autorzy:
    Qasim, Rafi Mohammed
    Jabbar, Tahseen Ali
    Faisal, Safaa Hameed
    Powiązania:
    https://bibliotekanauki.pl/articles/36063658.pdf
    Data publikacji:
    2023
    Wydawca:
    Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
    Tematy:
    hydrodynamic
    laminar flow
    open channel
    pier
    splitter plate
    Opis:
    The present analysis focuses on the investigation of the two-dimensional flow passing a bridge pier nearby a splitter plate in different regimes of a laminar flow. The splitter plate is T-shaped and two different cases have been studied based on the form of the splitter plate relative to the bridge pier. The analysis is implemented for steady and incompressible water flow in an open channel. The current study deals with velocity vectors, drag coefficients, lift coefficients, and skin friction. The analysis of the velocity vector gave a good indicator about the separation process and dissipation, which occurs at the splitter plate before the occurrence of these processes at the front face of the pier, especially the flow separation process. Moreover, the velocity vector gave a good image about the flow direction at two regions, the first region is located between the rear portion of the splitter plate and the frontal face of the pier, while the second region is the wake region, which is located at the downstream of the pier. Negative drag coefficient, lift coefficient, and skin friction coefficient values are obtained from the analysis. This happens due to the existence of the splitter plate that leads to the reduction of these values.
    Źródło:
    Scientific Review Engineering and Environmental Sciences; 2023, 32, 2; 135-154
    1732-9353
    Pojawia się w:
    Scientific Review Engineering and Environmental Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lagrangian Model for a Single Saltating Grain in the Near-Wall Region of an Open-Channel Flow
    Autorzy:
    Czernuszenko, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/241181.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    Lagrangian model
    open-channel flow
    particle-particle interaction
    Opis:
    A mathematical model for the continuous saltation of a particle near the granular bed in an open-channel flow is developed in detail. The model is based on the Lagrangian equations governing particle motion, and it takes into account the following forces: drag, lift, gravitation, virtual mass and the force responsible for particle-particle interactions. A model of particle-particle collisions is developed and used to determine the mean impulsive force acting upon a particle flowing and rebounding from the channel bed. The model can simulate the continuous saltation trajectories of a single particle in the near-bed region of turbulent flows, in which particle motion is controlled by collisions. The model has been calibrated and verified with available published data in a rather wide range of grain sizes from 0.53 mm to 15 mm. All parameters, such as lift, drag, restitution, friction coefficients and roughness height, have been set on the basis of a reanalysis of these published data.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2013, 60, 1-4; 31-50
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characteristic of Vertical Reynolds Shear Stress in a Patchy Heterogeneous Open Channel
    Autorzy:
    Olatunji, Peter Folorunso
    Powiązania:
    https://bibliotekanauki.pl/articles/1177793.pdf
    Data publikacji:
    2018
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Reynolds Stress
    gravel
    heterogeneous
    open channel
    patchy
    turbulence
    vegetation
    Opis:
    In turbulent flow, the Reynolds stress provides an understanding of the shear dispersion within the flow. Turbulence can be said to have an effect equivalent to the Reynolds shear stresses and are indicators of turbulence transport. This paper examined the characteristic of vertical Reynolds Shear stress in a patchy heterogeneous open channel using two experimental conditions for flexible and rigid vegetation interaction with gravel bed. The results show the value of vertical Reynolds stress decreases downstream along the channel section and as the distance from change in roughness increases. This is attributed to the effects of the bed roughness configuration (due to the preceding vegetated bed roughness) on the vertical Reynolds stress distribution. However, the position of maximum vertical Reynolds stress is located near bed over the vegetated zone. This provides an indication that the vegetated bed serves as the primary source of turbulence for the flow.
    Źródło:
    World Scientific News; 2018, 99; 1-14
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow
    Autorzy:
    Machalińska-Murawska, J.
    Szydłowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/973864.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open channel flow
    mathematical modeling
    numerical simulation
    FDM schemes
    Opis:
    Two explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free surface water flow. Two numerical simulations of flow with different hydraulic characteristics were performed – the first one for the extreme flow of the dam-break type and the second one for the simplified flood wave propagation problem. The computational results are compared to each other and to arbitrary solutions.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2013, 60, 1-4; 51-62
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical simulation of open channel flow between bridge piers
    Autorzy:
    Szydłowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934025.pdf
    Data publikacji:
    2011
    Wydawca:
    Politechnika Gdańska
    Tematy:
    numerical simulation
    open channel flow
    mathematical modeling
    bridge piers
    Opis:
    Free-surface flow in the vicinity of bridge piers on a fixed channel bed is a classical problem of open-channel hydraulics. This problem is usually analyzed using one-dimensional hydraulic models for steady-flow problems. The aim of this paper is to present a two-dimensional numerical simulation of water flow around obstacles, such as cylinders, which can act as a simplified model of real piers. The depth-averaged Navier-Stokes equations describing unsteady free-surface flow are solved using an explicit scheme of the finite-volume method. The numerical solution prepared for the simulations of unsteady free-surface flows was used here to analyze the case of steady flow. A numerical simulation of flow in the channel with the obstruction was performed for two different inflow discharges determining, respectively, the subcritical and supercritical flow in the cross-section of a channel constriction. In the second simulation, a hydraulic jump was observed downstream of the bridge section. The numerical results were compared with measurements. Water surface profiles were measured for both discharges in the hydraulic laboratory of the Faculty of Civil and Environmental Engineering at Gdansk University of Technology (GUT). Comparisons with laboratory data showed that the proposed approach constitutes a sufficiently accurate and reliable technique for predicting basic flow parameters. The method of two-dimensional modeling of flow in a river channel between bridge piers can be also integrated with the simulation of unsteady flood wave propagation, ensuring a uniform approach to the problem of flood modeling in river valleys. Moreover, a two-dimensional simulation yields detailed information about flow structure near the obstruction, which can be used to better elucidate debris transport and river bed deformation processes.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2011, 15, 3-4; 271-282
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical Modelling of Fish Passage with Turning Pools
    Autorzy:
    Maniecki, Ł.
    Powiązania:
    https://bibliotekanauki.pl/articles/241474.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open channel flow
    fishway
    turbulence
    numerical model
    turning pool
    Opis:
    An assessment of operating conditions in a baffled fish passage with pool dimensions of 2:2 3:0 m, and 180 horizontally turning pools, was carried out using numerical computations and a site survey of water flow velocity distribution. Velocity was measured with a PMS electromagnetic flowmeter and a hydrometric current meter in representative cross-sections of the fish passage in the pool centres and in the baffle barrier cross-section area. Numerical computations were also performed for two alternative baffle locations in the fishway. One reflected the actual conditions, and the other was an alternative arrangement designed to improve hydraulic conditions for fish migration. The numerical model used the Large Eddy Simulation (LES) method, which makes it possible to detect large vortexes. The study pays close attention to the velocity field analysis as well as the distribution and sizes of vortexes in the turning pool of the culvert. The results of numerical computations and the site survey show high consistency, and the proposed baffle placement modification significantly improves flow conditions, especially in the entry section of the passage.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2018, 65, 1; 41-66
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hydraulic Loss Coefficients in 1D Flows
    Autorzy:
    Sawicki, J. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/241418.pdf
    Data publikacji:
    2007
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    hydraulic loss
    closed-conduits flows
    water hammer
    open channel flow
    Opis:
    Determination of hydraulic losses is a very important problem, both from the cognitive and practical points of view. For the uniform and steady fluid streams these losses are described by the well known algebraic expressions, containing some experimental coefficients. In technical practice it is commonly assumed, that these coefficients can be applied also for more complex kinds of flow (non-uniform and even unsteady). However, the problem analysis shows that the proper level of conformity between the results of calculations and measurements can be obtained only after a considerable enlargement of the loss coefficient. Investigation of available characteristics of non-uniform and unsteady 1D velocity fields, presented in this article, leads to the conclusion that this enlargement is physically justified and in some cases it is possible to determine correction factors, which enable recalculation of "basic" coefficients into their new values, suitable for more complex models of 1D flows.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2007, 54, 2; 95-116
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental Analysis of Relations Between Coherent Turbulent Structures and Formation of Bedforms
    Autorzy:
    Termini, D.
    Sammartano, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/241077.pdf
    Data publikacji:
    2008
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open channel flow
    sediment transport
    bed forms
    flow turbulence structure
    Opis:
    The present paper describes an experimental investigation on the interactions between flow turbulence and sediment motion. During the experiments, detailed measurements of flow velocity components were carried out using an Acoustic Doppler Velocimeter (ADV). The occurrence of turbulent events (inward interaction, ejection, sweep and burst) was verified through conditioned quadrant analysis. The quantitative information on the spatial and temporal evolution of turbulent events was obtained through space-time correlations of the conditioned data. As the primary objective was to analyse how turbulent structures influence formation of bedforms, the spatial scale of turbulent event evolution has been compared with the wavelength of bed-forms (alternate bars) observed on the bed. The analysis has essentially highlighted that such spatial scale compares well with the wavelength of the bars.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2008, 55, 3-4; 125-143
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The application of cumulants to flow routing
    Autorzy:
    Romanowicz, Renata J.
    Doroszkiewicz, Joanna
    Powiązania:
    https://bibliotekanauki.pl/articles/108562.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
    Tematy:
    open channel flow
    linearized St. Venant equation
    analytical solutions
    moments
    cumulants
    Opis:
    This paper aims to fill a gap between present and past research approaches to modelling flow in open channels. In particular, a history of the analytical solutions of a linearized St. Venant equation is presented. A solution of the linearized St. Venant equation, describing the response of a river channel to a single impulse forcing, the so called Instantaneous Unit Hydrograph (IUH), can be described using cumulants, defined as the moments of a logarithm of a variable. A comparison of analytical and numerical solutions of flood wave propagation under various flow conditions is given. The river reach of Biała Tarnowska is used as an illustration of both approaches. A practical application of simplified solutions to the emulator of a flood wave propagation is suggested showing a link between theory and practice.
    Źródło:
    Meteorology Hydrology and Water Management. Research and Operational Applications; 2019, 7, 1; 15-21
    2299-3835
    2353-5652
    Pojawia się w:
    Meteorology Hydrology and Water Management. Research and Operational Applications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental Analysis of Horizontal Turbulence of Flow over Flat and Deformed Beds
    Autorzy:
    Termini, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/241285.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open-channel flow
    flow turbulence structure
    burst cycle
    bed forms
    laboratory experiments
    Opis:
    Laboratory experiments in a straight flume were carried out to examine the evolution of large-scale horizontal turbulent structures under flat-bed and deformed-bed conditions. In this paper, the horizontal turbulence of flow under these conditions is analyzed and compared. The conditioned quadrant method is applied to verify the occurrence of turbulent events. The distributions of horizontal Reynolds shear stress and turbulent kinetic energy are also presented and discussed. Results show the occurrence of an “initial” sequence of horizontal vortices whose average spatial length scales with the channel width. Under deformed-bed conditions, this spatial length does not change.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2015, 62, 3-4; 77-99
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A turbulence model for 3-d flows with anisotropic structure of turbulence
    Autorzy:
    Czernuszenko, W.
    Rylov, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/241364.pdf
    Data publikacji:
    2005
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    3D flow
    mathematical model
    numerical simulation
    open channel flow
    turbulence model
    Opis:
    A new turbulence model for flows in open channels with compound cross-sections is presented. The structure of turbulence in these channels can be anisotropic. This structure is described by the turbulent stress tensor that is presented here as the sum of two tensors, namely, normal and shear stress tensors. The normal and shear turbulent stresses are expressed by the turbulence intensities and the mixing length tensor (MLT), respectively. The turbulence intensities can be learned from measurements or another suitable approaches. One such approach that allows calculating the main component of the normal stresses is presented in the paper. The components of MLT are defined based on a new concept of generic mixing length (GML). The generic mixing length is assumed to depend on both distances; from the nearest wall and from the water surface. To demonstrate how the new model works the basic hydrodynamic equations (parabolic approximation of Reynolds equations) together with the turbulence model are solved. The well-known Patankar and Spalding (1972) algorithm was used when solving these equations. A series of numerical simulations were performed for different components of MLT and different channel geometries.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 4; 303-320
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of Average Energy Slope Estimation Formulas for One-dimensional Steady Gradually Varied Flow
    Autorzy:
    Artichowicz, W.
    Mikos-Studnicka, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/241083.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open channel
    steady flow
    gradually varied flow
    standard step method
    energy slope
    Opis:
    To find the steady flow water surface profile, it is possible to use Bernoulli’s equation, which is a discrete form of the differential energy equation. Such an approach requires the average energy slope between cross-sections to be estimated. In the literature, many methods are proposed for estimating the average energy slope in this case, such as the arithmetic mean, resulting in the standard step method, the harmonic mean and the geometric mean. Also hydraulic averaging by means of conveyance is commonly used. In this study, water surface profiles numerically computed using different formulas for expressing the average slope were compared with exact analytical solutions of the differential energy equation. Maximum relative and mean square errors between numerical and analytical solutions were used as measures of the quality of numerical models. Experiments showed that all methods gave solutions useful for practical engineering purposes. For every method, the numerical solution was very close to the analytical one. However, from the numerical viewpoint, the differences between the methods were significant, as the errors differed up to two orders of magnitude.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2014, 61, 3-4; 89--109
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flow in a skewed compound open channel with trees on a flood plain
    Autorzy:
    Fukui, Y.
    Urayama, T.
    Takamizu, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/241408.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    skewed compound open channel
    trees on the flood plain
    drag force
    secondary flow
    Opis:
    In this research, the flow in a skewed compound channel with trees on the flood plain along the skewed part is studied. Three cases are assumed. Namely, 1) there are no trees on the flood plain along the main skewed part; 2) there are many trees on the flood plain set in order; and 3) there are many trees on the flood plain in disorder. In this research, 1) changes of water level and velocity in the channel; 2) the de-velopment of secondary flow as water flows downward; 3) the drag force due to the existence of trees; and 4) the changes of the river bed level in a movable bed condition are investigated. Numerical analyses using 2-D shallow water theory are also carried out to reproduce a flow in the skewed channel. As a result, the hydraulic quantities, for example water depth and the velocity cal-culated for a case setting trees in order and close together, are available in the river planning for a situation in which some of the trees were washed downstream. Such hydraulic quantities become severe for conditions in order and close to-gether in the flood. During the experiment using sand, channel beds are deformed by piling up and digging of sands or stones in various cases.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 1; 3-19
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical study on two dimensional distribution of streamwise velocity in open channel turbulent flows with secondary current effect
    Autorzy:
    Mohan, S.
    Kundu, S.
    Ghoshal, K.
    Kumar, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/38616700.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Podstawowych Problemów Techniki PAN
    Tematy:
    velocity distribution
    open channel flow
    turbulent flow
    RANS equations
    secondary current
    finite difference method
    Opis:
    For studying mechanism of sediment transport in river flows, open channel flow is a prototype. Flow has always three components of velocity for all types of channel geometry and for a time independent uniform flow along streamwise or main flow direction, all the components of velocity are functions of lateral and vertical coordinates. The present study investigates the two dimensional distribution of streamwise (or longitudinal) velocity starting from the Reynolds averaged Navier–Stokes equation for a turbulent open channel flow which is steady and uniform along the main flow direction. Secondary flows both along the vertically upward direction and along the lateral direction are considered which are also taken as functions of lateral and vertical coordinates. Inclusion of the secondary current brings the effect of dip phenomenon in the model. The resulting second order partial differential equation is solved numerically. The model is validated for all the cross-sectional, transverse and centreline velocity distribution by comparing with existing relevant set of experimental data and also with an existing model. Comparison results show good agreement with data as well as with the previous model proving the efficiency of the model. It is found that the transverse velocity distribution depends on the formation of circular vortex in the cross-sectional plane and becomes periodic as the number of circular vortex increases for increasing aspect ratios.
    Źródło:
    Archives of Mechanics; 2021, 73, 2; 175-200
    0373-2029
    Pojawia się w:
    Archives of Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical Analysis of Turbulent Flow over a Backward-facing Step in an Open Channel
    Autorzy:
    Saleem, Bala Kawa M.
    Mustafa, Andam
    Kareem, Dalshad Ahmed
    Yuce, Mehmet Ishak
    Szydłowski, Micchał
    Al-Ansari, Nadhir
    Powiązania:
    https://bibliotekanauki.pl/articles/31340451.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open channel
    backward-facing step
    reattachment length
    expansion ratio
    Kɛ- model
    Kω- model
    Opis:
    Computational examinations of the flow field in an open channel having a single Backward- -Facing Step (BFS) with a constant water depth of 1.5 m were performed. The effects of the expansion ratio, and the flow velocity along the reattachment length, were investigated by employing two different expansion ratios of 1.5 and 2, and eight various flow velocities of 0.5, 1, 2, 3, 4, 5, 7.5 and 10 m/sec in the Computational Fluid Dynamic (CFD) simulations. Commercially available CFD software, ANSYS FLUENT, was used for calculations. The simulation outcomes were verified using experimental results. Moreover, analyses were performed by using two equation turbulence closure models, K-ε family (standard, RNG and realizable), and K-ω family (Wilcox’s and SST K-ω). The analyses have revealed that the reattachment length increases with an increase in the expansion ratio, the flow velocity and the Reynolds number. The results obtained for two expansion rates and eight different flow velocities have shown insignificant differences between one turbulence closure model and the others. Furthermore, it was observed that both velocity and expansion ratios have an effect on the reattachment zone size.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2023, 70, 1; 49-69
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Koncepcja stanowiska do badania wypływu zanieczyszczeń z kanałów burzowych
    Concept of an experimental stand for study the outflow of pollutants from combined sewer overflows
    Autorzy:
    Rząsa, M. R.
    Boguniewicz-Zabłocka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/268350.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
    Tematy:
    przepływ w kanale otwartym
    przepływ dwufazowy
    komputerowa analiza obrazu
    open channel flow
    two-phase flow
    computer image processing
    Opis:
    Pomiary przepływu mieszaniny polidyspersyjnej są jednymi z najtrudniejszych do zrealizowania w warunkach technicznych. W artykule opisano koncepcję systemu pomiarowego, który umożliwi obserwację przepływającej mieszaniny oraz wyznaczenia podstawowych parametrów jej ruchu. W pracy zaproponowano sposób opisu wydmy przesuwającego się piasku. Wymiary wydmy zdefiniowano za pomocą czterech charakterystycznych wymiarów. Zaproponowano stanowisko laboratoryjne umożliwiające badanie przepływu mieszaniny w kanale otwartym przy różnym nachyleniu kanału i różnym składzie granulometrycznym frakcji stałej. Stanowisko wyposażono w system rejestracji obrazu. Obrazy zarejestrowane kamerą poddawane są procesowi komputerowej analizy obrazu i na tej podstawie możliwe jest określenie podstawowych parametrów ruchu mieszaniny. Praca zawiera opis koncepcji stanowiska laboratoryjnego oraz ideę metody analizy obrazu.
    A storm water system with open channels for the discharge of rainwater exists in most urbanised areas. The flow in these kind of channels is generally multiphase flow, in which there are solids and liquids and in some places there may be an additional gas phase. Therefore the ability to describe such flow is reduces to the description of the motion of the polydisperse mixture. Polydisperse mixture flow measurements are among the most difficult to achieve in technical terms. The article describes the concept of a measurement system that allows observation of the poly-dispersed flow and determine the basic parameters of its motion. Concept of experimental laboratory set-up was proposed to measure the parameters of the polydispersed mixture flow process in open channel with different slope of the channel and various granulometry of the solid fraction. In this work description of sand dunes with four typical parameters was proposed. A digital camera is used to interrogate the flow. Images recorded on the camera will be subjected to a process of image analysis, and from this the basic parameters of the movement are determined. The work includes a description of the experimental set-up with the idea of image analysis methods.
    Źródło:
    Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2015, 47; 155-158
    1425-5766
    2353-1290
    Pojawia się w:
    Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Impact of Energy Slope Averaging Methods on Numerical Solution of 1D Steady Gradually Varied Flow
    Autorzy:
    Artichowicz, W.
    Prybytak, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/240952.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    standard step method
    numerical integration
    initial-value problem
    ordinary differential equation
    open channel
    steady gradually varied flow
    energy slope
    Opis:
    In this paper, energy slope averaging in the one-dimensional steady gradually varied flow model is considered. For this purpose, different methods of averaging the energy slope between cross-sections are used. The most popular are arithmetic, geometric, harmonic and hydraulic means. However, from the formal viewpoint, the application of different averaging formulas results in different numerical integration formulas. This study examines the basic properties of numerical methods resulting from different types of averaging.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2015, 62, 3-4; 101-119
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of membrane techniques for municipal wastewater treatment and reuse
    Zastosowanie technik membranowyoh do odzyszozania ścieków i ich ponownego wykorzystania
    Autorzy:
    Pervov, A.
    Spitsov, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/400277.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    ścieki bytowe
    osad ściekowy
    nanofiltracja
    odwrócona osmoza
    odzysk
    regeneracja
    membrane fouling
    nanofiltration
    open-channel module
    reclamation
    recovery
    reverse osmosis
    sludge dewatering
    spiral wound module
    domestic wastewater
    Opis:
    State-of-the-art chemical, physical and biological water treatment techniques do not always properly remove some biogenic elements (nitrates, ammonia and phosphates) to reuse or reclaim wastewater. Modern membrane techniques provide high efficiency in removal of suspended and colloidal matter, bacteria and viruses, organic compounds as well as dissolved ions. For wastewater reuse and reclamation application of reverse osmosis provides reduction of BOD, phosphates and ammonia without application of biological treatment. To successfully apply reverse osmosis to treat wastewater, adequate pretreatment is required. Often pretreatment costs even exceed reverse osmosis facilities costs. Long research in fouling and scaling mechanisms revealed that fouling rates are dependent not only on hydrodynamic factors, but on membrane properties and channel configuration as well. Therefore, development of a new type of membrane channel with improved hydraulic and fouling characteristics enabled us to present efficient water treatment techniques for wastewater treatment and reclamation. Schematic flow diagrams are presented for different wastewater treatment cases, such as car washing and laundry effluent as well as domestic wastewater treatment and reuse.
    Dostępne techniki chemicznego, fizycznego i biologicznego oczyszczania nie zawsze są w stanie efektywnie usuwać związki biogenne (azotany, azot amonowy, fosforany) w celu ponownego użycia oczyszczonych ścieków. Nowoczesne techniki membranowe zapewniają wysoką efektywność usuwania zawiesiny rozpuszczonej i koloidalnej, bakterii, wirusów, związków organicznych i rozpuszczonych jonów. Zastosowanie techniki membranowej w celu odzysku wody ze ścieków nie wymaga stosowania biologicznego oczyszczania ścieków. Efektywne zastosowanie procesów membranowych wymaga wstępnego oczyszczania ścieków, którego koszty mogą przewyższać te związane z eksploatacją membran.
    Źródło:
    Inżynieria Ekologiczna; 2011, 24; 107-119
    2081-139X
    2392-0629
    Pojawia się w:
    Inżynieria Ekologiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sukcesja osadowa i etapy formowania ozu gostynińskiego, Równina Kutnowska, centralna Polska
    Autorzy:
    Roman, Małgorzata
    Powiązania:
    https://bibliotekanauki.pl/articles/763122.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
    Tematy:
    esker, facies analysis, sedimentary environment, subglacial tunnel, ice-open channel, Late Vistulian ice sheet margin, central Poland
    oz, analiza litofacjalna, środowisko sedymentacji, tunel subglacjalny, otwarta szczelina, lądolód późnego Vistulianu, centralna Polska
    Opis:
    Well-developed N-S trending esker, described in literature as the Gostynin esker, consists of parallel ridges associated witch a tunnel valey flanked by the Vistulian (Weichselian) till plain. The sedimentary succession of one of the ridges is known in the Osada site. Complexity of the esker internal structure is expressed by 4 sedimentary units of different environments. The lowest, coarsegravelly (O1), developed by infilling a subglacial tunnel. The following one, making the main part of the esker ridge, is a sandy unit (O2) deposited in an ice-walled open channel. Locally, the deposits show normal synsedimentary faults. The O3 unit of fine-grained sediments was laid in a stagnant water. The succession is topped by a thin discontinous layer of flow till (O4). Sedimentation took place when the ice-sheet changed its dynamics from active to stagnant.
    Artykuł nie zawiera streszczenia w języku polski.
    Źródło:
    Annales Universitatis Mariae Curie-Sklodowska, sectio B – Geographia, Geologia, Mineralogia et Petrographia; 2016, 71, 1
    0137-1983
    Pojawia się w:
    Annales Universitatis Mariae Curie-Sklodowska, sectio B – Geographia, Geologia, Mineralogia et Petrographia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of membranes to treat natural and waste waters: new considerations to reduce fouling and increase recovery Up to 99%
    Zastosowanie membran do oczyszczania wody i ścieków: nowe aspekty zmniejszenia zanieczyszczenia i zwiększenia odzysku do 99%
    Autorzy:
    Pervov, A.
    Andrianov, A.
    Gorbunova, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/400299.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    ścieki bytowe
    nanofiltracja
    odwrócona osmoza
    odzysk
    regeneracja
    domestic wastewater
    fouling-free technologies
    membrane fouling
    nanofiltration
    natural water treatment
    open-channel module
    reclamation
    recovery
    reverse osmosis
    scaling
    spiral wound module
    urban surface water
    zero discharge
    Opis:
    Survey shows that high operational costs of membrane facilities and large amounts of effluents are mainly attributed to fouling and scaling. Research of scaling and fouling mechanisms showed that these processes depend not only on hydraulic and hydrodynamic factors, but on membrane type, material and channel configuration as well. Operational parameters of different membrane configurations show that spiral wound modules demonstrate best hydraulic and hydrodynamic characteristics combined with lowest price. Main ways to develop new fouling-free techniques are outlined that require modified "open-chan-nel" spiral wound membranes. Elimination of "deadlocks" as a main cause of scaling and fouling provide new technological approach to develop water treatment techniques without pretreatment facilities and chemicals. Modification of channel provides possibility to reach high recoveries and high supersaturation values due to strong stability of calcium carbonate solutions. Membrane transport is not only purification instrument it is also a reactor to coagulate, concentrate and precipitate water constituents on membrane surface. Several examples of water treatment flow diagrams are presented to demonstrate principles of zero concentrate flow discharge. Coagulated suspended matter after membrane flushes is collected, sedimented and finally dewatered. The dewatered sludge contains averagely 0,8 per cent of initial water. Due to the use of an "open-channel" modules membrane brine flow could be concentrated by many times without a fear of scaling and added to the sludge. Thus the excessive salts and impurities could be withdrawn from water systems together with partially dewatered sludge. Similarly excessive calcium carbonate could be also concentrated in membrane modules and subsequently precipitated, sedimented and dewatered. Solution of fouling problems thus provides a new approach to save operational costs and to increase ecological efficiency of membrane water treatment tools.
    Badania wykazują, iż wysokie koszty eksploatacji urządzeń z zastosowaniem membran i duże ilości odcieków są przypisywane zanieczyszczeniom i odkładaniu się kamienia. Procesy te zależą nie tylko od czynników hydraulicznych i hydrodynamicznych, ale także od rodzaju membran i materiałów użytych do ich budowy. Parametry pracy różnych membran wykazały najlepsze właściwości modułów spiralnych przy najniższej cenie. Przepływ przez membrany nie ogranicza się jedynie do oczyszczania, jest to także reaktor do koagulacji, zatężania i strącania. Zawiesina po procesie koagulacji z procesu czyszczenia membran jest poddana sedymentacji i odwadnianiu. Osad z odwadniania zawiera około 8% wody. Zastosowanie modułów o "otwartych kanałach" powoduje zmniejszenie zagrożenia zanieczyszczenia i odkładania się kamienia. Rozwiązanie problemu zmniejszenia zanieczyszczenia membran pozwoli zmniejszyć koszty pracy instalacji i spowoduje wyższy poziom ekologicznej efektywności narzędzi wykorzystujących technikę membranową.
    Źródło:
    Inżynieria Ekologiczna; 2011, 24; 17-31
    2081-139X
    2392-0629
    Pojawia się w:
    Inżynieria Ekologiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Measurements of 3D turbulence structure in a compound channel
    Autorzy:
    Czernuszenko, W.
    Kozioł, A.
    Rowiński, P. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/241134.pdf
    Data publikacji:
    2007
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    open channels
    compound channel
    turbulence
    measurements
    Opis:
    The paper describes some turbulence measurements carried out in an experimental compound channel with flood plains. The surface of the main channel bed was smooth and made of concrete, whereas the floodplains and sloping banks were covered by cement mortar composed with terrazzo. Instantaneous velocities were measured be means of a three-component acoustic Doppler velocity meter (ADV) manufactured by Sontek Inc. This article presents the results of measurements of primary velocity, the distribution of turbulent intensities, Reynolds stresses, autocorrelation functions, turbulent scales, as well as the energy spectra.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2007, 54, 1; 55-73
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Network Information Hiding and Science 2.0 : Can it be a Match?
    Autorzy:
    Wendzel, S.
    Caviglione, L.
    Mazurczyk, W.
    Lalande, J. F.
    Powiązania:
    https://bibliotekanauki.pl/articles/226567.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    network steganography
    information hiding
    steganography
    Science 2.0
    open science
    covert channel
    Opis:
    Science 2.0 aims at using the information sharing and collaborative features of the Internet to offer new features to the research community. Science 2.0 has been already applied to computer sciences, especially bioinformatics. For network information hiding, a field studying the possibility of concealing a communication in networks, the application of Science 2.0 is still a rather uncovered territory. To foster the discussion of potential benefits for network information hiding, we provide a disquisition for six different Science 2.0 aspects when applied to this domain.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 2; 217-222
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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