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    Wyświetlanie 1-18 z 18
    Tytuł:
    Evaluation of liquid-gas flow in pipeline using gamma-ray absorption technique and advanced signal processing
    Autorzy:
    Hanus, Robert
    Zych, Marcin
    Mosorov, Volodymyr
    Golijanek-Jędrzejczyk, Anna
    Jaszczur, Marek
    Andruszkiewicz, Artur
    Powiązania:
    https://bibliotekanauki.pl/articles/1848957.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    two-phase flow
    void fraction
    gamma-ray absorption
    flow regime identification
    artificial neural network
    Opis:
    Liquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of the gamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble, and bubble one. In the research, a radiometric set consisting of two Am-241 sources and two NaI(TI) scintillation detectors have been applied. Based on the analysis of the signals from both scintillation detectors, the gas phase velocity was calculated using the cross-correlation method (CCM). The signal from one detector was used to determine the void fraction and to recognise the flow regime. In the latter case, a Multi-Layer Perceptron-type artificial neural network (ANN) was applied. To reduce the number of signal features, the principal component analysis (PCA) was used. The expanded uncertainties of gas velocity and void fraction obtained for the flow types studied in this paper did not exceed 4.3% and 7.4% respectively. All three types of analyzed flows were recognised with 100% accuracy. Results of the experiments confirm the usefulness of the gamma-ray absorption method in combination with radiometric signal analysis by CCM and ANN with PCA for comprehensive analysis of liquid-gas flow in the pipeline.
    Źródło:
    Metrology and Measurement Systems; 2021, 28, 1; 145-159
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Some problems of hydrodynamics of two-phase flow mixtures in minichannels
    Autorzy:
    Wengel, M.
    Miłaszewicz, B.
    Ulbrich, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/240674.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    two-phase flow
    minichannel
    flow pattern
    flow regime map
    przepływ dwufazowy
    minikanał
    model przepływu
    mapa przepływu
    Opis:
    Gas-liquid two-phase flow in minichannels has been the subject of increased research interest in the past few years. Evaluation, however, of today's state of the art regarding hydrodynamics of flow in minichannels shows significant differences between existing test results. In the literature there is no clear information regarding: defining the boundary between minichannels and conventional channels, labelling of flow patterns. The review of literature on the hydrodynamics of gas-liquid flow in minichannels shows that, despite the fact that many research works have been published, the problem of determining the effect of diameter of the minichannel on the hydrodynamics of the flow is still at an early stage. Therefore, the paper presents the results of research concerning determination of flow regime map for the vertical upward flow in minichannels. The research is based on a comprehensive analysis of the literature data and on the research that has been carried out. Such approach to the mentioned above problems concerning key issues of the two-phase flow in minichannels allowed to determine ranges of occurrence of flow structures with a relatively high accuracy.
    Źródło:
    Archives of Thermodynamics; 2014, 35, 2; 93-101
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Parametric sensitivity of a CFD model concerning the hydrodynamics of trickle-bed reactor (TBR)
    Autorzy:
    Janecki, D.
    Burghardt, A.
    Bartelmus, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/184944.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hydrodynamics
    trickle-flow regime
    pressure gradient
    liquid holdup
    phases interaction
    CFD
    hydrodynamika
    gradient ciśnienia
    Opis:
    The aim of the present study was to investigate the sensitivity of a multiphase Eulerian CFD model with respect to relations defining drag forces between phases. The mean relative error as well as standard deviation of experimental and computed values of pressure gradient and average liquid holdup were used as validation criteria of the model. Comparative basis for simulations was our own data-base obtained in experiments carried out in a TBR operating at a co-current downward gas and liquid flow. Estimated errors showed that the classical equations of Attou et al. (1999) defining the friction factors Fjk approximate experimental values of hydrodynamic parameters with the best agreement. Taking this into account one can recommend to apply chosen equations in the momentum balances of TBR.
    Źródło:
    Chemical and Process Engineering; 2016, 37, 1; 97-107
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Void fraction and flow regime determination by means of MCNP code and neural network
    Autorzy:
    Rabiei, A.
    Shamsaei, M.
    Kafaee, M.
    Shafaei, M.
    Mahdavi, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/146656.pdf
    Data publikacji:
    2012
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    flow regime
    gamma-ray densitometry
    neural network (NN)
    Monte Carlo N-particle (MCNP)
    void fraction
    Opis:
    One of the non-intrusive and accurate methods of measuring void fraction in two-phase gas liquid pipe flows is the use of the gamma-transmission void fraction measurement technique. The goal of this study is to describe low-energy gamma-ray densitometry using an 241Am source for the determination of void fraction and flow regime in water/gas pipes. The MCNP code was utilized to simulate electron and photon transport through materials with various geometries. Then, a neural network was used to convert multi-beam gamma-ray spectra into a classification of the flow regime and void fraction. The simulations cover the full range of void fraction with Bubbly, Annular and Droplet flows. By using simulation data as input to the neural networks, the void fraction was determined with an error less than 3% regardless of the flow regime. It has thus been shown that multi-beam gamma-ray densitometers with a detector response examined by neural networks can analyze a two-phase flow with high accuracy.
    Źródło:
    Nukleonika; 2012, 57, 3; 345-349
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wieloletnia i sezonowa dynamika niżówek w Warcie w Sieradzu
    Multiannual and seasonal dynamics of low-flows in the Warta river in Sieradz
    Autorzy:
    Kozek, M.
    Tomaszewski, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/338218.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Technologiczno-Przyrodniczy
    Tematy:
    niedobory odpływu niżówkowego
    reżim przepływów niżówkowych
    susza hydrologiczna
    drought streamflow deficits
    hydrological drought
    low-flow regime
    Opis:
    Badaniami dynamiki niżówek w Warcie w Sieradzu objęto okres 1971–2000. Analizy dokonano na podstawie serii przepływów dobowych, udostępnionych przez IMGW-PIB. Niżówki zidentyfikowano na podstawie stałego przepływu granicznego, przyjmując za poziom odcięcia rzędną Q70% z krzywej czasów trwania przepływów wraz z wyższymi. Analizie poddano wieloletnią i sezonową dynamikę objętości niedoboru odpływu, czasu trwania niżówki oraz estymatora częstości pojawiania się badanych zjawisk ekstremalnych w postaci odstępu międzyniżówkowego. W oparciu o uzyskane wyniki dokonano oceny struktury kształtowania się niżówek w zakresie ich zmienności i cech rozkładu statystycznego. Zbadano tendencje wieloletnie, w których zaobserwowano liniowe trendy zmian badanych charakterystyk. Za pomocą współczynnika korelacji dokonano oceny stabilności niżówek w kolejnych miesiącach roku hydrologicznego. Ponadto zbadano jednorodność genetyczną niżówek w Warcie za pomocą krzywej podwójnie kumulowanej oraz oszacowano długość maksymalnej niżówki o prawdopodobieństwie nieprzekroczenia 95% i 99%.
    Investigations of low-flow dynamics in the Warta River in Sieradz were conducted for the period 1971–2000. Analyses were based on daily discharge series, made available by Polish Institute of Meteorology and Water Management – National Research Institute. Low-flows were identified on the base of threshold level method where 70th percentile of the flow duration curve was established as truncation level. Studies included multiannual and seasonal dynamics of drought streamflow deficit volume, low-flow duration as well as inter-low-flow spacing which was taken as a frequency estimator of hydrological extremes occurrence. On the base of results the structure of low-flow forming was assessed, especially in the field of its variability and statistical distribution. There were investigated multiannual tendencies where linear trends of changes of studied characteristics were observed. On the base of correlation coefficient lowflows stability on the consecutive months of the hydrological year was analysed. Moreover, low-flow genetic homogeneity of the Warta River was investigated on the base of double-mass curve. There also was estimated non-exceedance probability of maximum low-flow duration at significance level of 95% and 99%.
    Źródło:
    Woda-Środowisko-Obszary Wiejskie; 2018, 18, 2; 41-56
    1642-8145
    Pojawia się w:
    Woda-Środowisko-Obszary Wiejskie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design and simulation of a multienergy gamma ray absorptiometry system for multiphase flow metering with accurate void fraction and water-liquid ratio approximation
    Autorzy:
    Khayat, Omid
    Afarideh, Hossein
    Powiązania:
    https://bibliotekanauki.pl/articles/147267.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    multiphase flow measurement
    void fraction
    water-liquid ratio
    flow regime
    MCNP
    artificial neural network
    reżim przepływu
    sztuczna sieć neuronowa
    Opis:
    Multiphase flow meters are used to measure the water-liquid ratio (WLR) and void fraction in a multiphase fluid stream pipeline. In the present study, a system of multiphase flow measurement has been designed by application of three thallium-doped sodium iodide scintillators and a radioactive source of 133Ba simulated by Monte Carlo N-particle (MCNP) transport code. In order to capture radiations passing across the pipe, two direct detectors have been installed on opposite sides of the radioactive source. Another detector has been placed perpendicular to the transmission beam emitted from the 133Ba source to receive radiations scattered from the fluid flow. Simulation was done by the MCNP code for different volumetric fractions of water, oil, and gas phases for two types of flow regimes, namely, homogeneous and annular; training and validation data have been provided for the artificial neural network (ANN) to develop a computation model for pattern recognition. Depending on applications of the neural system, several structures of ANNs are used in the current paper to model the flow measurement relations, while the detector outputs are considered as the input parameters of the neural networks. The first, second, and third structures benefit from two, three, and five multilayer perceptron neural networks, respectively. Increasing the number of ANNs makes the system more complicated and decreases the available data; however, it increases the accuracy of estimation of WLR and gas void fraction. According to the results, the maximum relative difference was observed in the scattering detector. It was clear that transmission detectors would demonstrate the difference between the flow regimes as well. It is necessary to note that the error calculated by the MCNP simulator is <0.5% for the direct detectors (TR1 and TR2). Due to the difference between the data of the two flow regimes and the errors of data in the simulation codes of the MCNP, it was possible to separate these flow regimes. The effect of changing WLR on the efficiency for a constant void fraction confi rms a considerable variance in the results of annular and homogeneous flow s occurring in the scattering detector. There is a similar trend for the void fraction; hence, one can easily distinguish changes in efficiency due to the WLR. Analysis of the simulation results revealed that in the proposed structure of the multiphase flow meter and the computation model used for simulation, the two flow regimes are simply distinguishable.
    Źródło:
    Nukleonika; 2019, 64, 1; 19-29
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Identification of constant and stable main transition velocity in bubble column reactors
    Określenie stałej i stabilnej prędkości przejściowej w reaktorach barbotażowych
    Autorzy:
    Nedeltchev, Stoyan
    Powiązania:
    https://bibliotekanauki.pl/articles/1955367.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Instytut Inżynierii Chemicznej PAN
    Tematy:
    bubble columns
    flow regime identification
    main transition velocity
    entropy analysis
    kolumny barbotażowe
    identyfikacja reżimu przepływu
    główna prędkość przejścia
    Opis:
    This work presents new results about the reliable identification of the main transition velocity Utrans-1 in different bubble columns (0.1 – 0.46 m in inner diameter) equipped with several perforated plate gas distributors. Two different gas-liquid systems (air-water and air-therminol LT) have been used. The most important finding in this work is that Utrans-1 (end of the homogeneous regime) occurs at 0.04 m·s-1 irrespective of the operating conditions studied. For the Utrans-1 identification, the following parameters have been used: Kolmogorov and reconstruction entropies, degree of randomness and information entropy.
    W pracy przedstawiono nowe wyniki dotyczące wiarygodnej identyfikacji głównej prędkości przejścia Utrans-1 w różnych kolumnach barbotażowych (o średnicy wewnętrznej 0,1 - 0,46 m) wyposażonych w kilka dystrybutorów gazu typu płyta perforowana. Zastosowano dwa różne układy gaz-ciecz (powietrzewoda i powietrze-therminol LT). Najważniejszym odkryciem w tej pracy jest to, że Utrans-1 (koniec reżimu przepływu homogenicznego) występuje dla prędkości 0,04 m·s-1 niezależnie od badanych warunków pracy. Do identyfikacji Utrans-1 wykorzystano następujące parametry: entropię Kołmogorowa, entropię rekonstrukcyjną, stopień losowości oraz entropię informacji.
    Źródło:
    Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk; 2020, 24; 9-27
    1509-0760
    Pojawia się w:
    Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Unsteady MHD thermal diffusive and radiative fluid flow past a vertical porous plate with chemical reaction in slip flow regime
    Autorzy:
    Ravi Kumar, D.
    Jayarami Reddy, K.
    Raju, M. C.
    Powiązania:
    https://bibliotekanauki.pl/articles/265452.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    swobodna konwekcja
    magnetohydrodynamika
    przenoszenie ciepła
    dyfuzja termiczna
    promieniowanie
    reakcja chemiczna
    poślizg
    MHD
    free convection
    heat and mass transfer
    slip flow regime
    thermal diffusion
    radiation
    chemical reaction
    Opis:
    An analytical solution of an MHD free convective thermal diffusive flow of a viscous, incompressible, electrically conducting and heat-absorbing fluid past a infinite vertical permeable porous plate in the presence of radiation and chemical reaction is presented. The flow is considered under the influence of a magnetic field applied normal to the flow. The plate is assumed to move with a constant velocity in the direction of fluid flow in slip flow regime, while free stream velocity is assumed to follow the exponentially increasing small perturbation law. The velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number distributions are derived and have shown through graphs and tables by using the simple perturbation technique.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2019, 24, 1; 117-129
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Litodynamiczna interpretacja środowiska fluwialnego na podstawie wskaźników uziarnienia : przegląd wybranych metod
    Lithodynamic interpretation of fluvial environment based on grain size compositions parameters : review of selected methods
    Autorzy:
    Szmańda, J. B.
    Powiązania:
    https://bibliotekanauki.pl/articles/294855.pdf
    Data publikacji:
    2010
    Wydawca:
    Stowarzyszenie Geomorfologów Polskich
    Tematy:
    aluwia
    wskaźniki uziarnienia
    interpretacja środowisk sedymentacji
    analiza trendów sedymentacji
    reżim energetyczny przepływu
    strefy morfogenetyczne
    alluvia
    grain size composition parameters
    sedimentological conditions interpretation
    sediment trend analysis
    energy flow regime
    morphogenetic zone
    Opis:
    W artykule omówiono wybrane metody interpretacji litodynamicznej środowiska fluwialnego. Przedstawiono metody oceny rangowej energii prądu, metody analizy trendów sedymentacyjnych w zakresie zmian wskaźników uziarnienia w procesie sedymentacji fluwialnej, modele interpretacji morfodynamicznej i transportu ziaren. Metody te zostały poddane ocenie merytorycznej na wybranych przykładach badań własnych i literatury.
    The grain size parameters (mean size, sorting, skweness, kurtosis, median and first percentile) could be used for the lithodynamic interpretation of fluvial environment. Dependency between a particle size and a sedimentologic condition in the fluvial environment have been defined (Ruby, 1933; Hjulström, 1935; Morris, 1957; Poole, 1957; Aipołow, 1963; Passega, 1964; Sundborga, 1967; Royse, 1968; Braithwaite, 1973; Southard and Boguchwal; 1973, Baker 1974; Kaniecki, 1976; Miller et. al, 1977; Koster, 1978; Middelton and Southard, 1978; Baba and Komar, 1981; Froehlich, 1982; Costa, 1983; Williams, 1983; Eschner and Kichner, 1984; Młynarczyk, 1985; Maizels, 1989; O’Connor, 1993; Mazumder 1994; Le Roux 1977, 2002; Ferguson and Church 2004). Shear and settlement velocity could be calculated on the base of the grain size. Sediment trend analysis will be used to the change of a grain size composition during erosion, transport and accumulation. Condition of the grain transport (traction, saltation and suspension) and energy flow regime will be evaluated on the based of the grain size parameters dependency diagrams. With the use of these diagrams the morphodynamic zones (erosion, balance and deposition) could be estimated. Selected methods of the fluvial environment lithodynamic interpretation were collected and decrypted in this article.
    Źródło:
    Landform Analysis; 2010, 12; 109-125
    1429-799X
    Pojawia się w:
    Landform Analysis
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    TYPOLOGIA REŻIMU ODPŁYWU RZEK W POLSCE W RÓŻNYCH FAZACH OSCYLACJI PÓŁNOCNOATLANTYCKIEJ
    Autorzy:
    Wrzesiński, Dariusz
    Powiązania:
    https://bibliotekanauki.pl/articles/943768.pdf
    Data publikacji:
    2018
    Wydawca:
    Poznańskie Towarzystwo Przyjaciół Nauk
    Tematy:
    river flow
    hydrological regime
    flow coefficient (Pardé)
    teleconnections
    Opis:
    The paper presents the spatial distribution of types of river regime in Poland according to the assumptions of Dynowska (1997) for three time scales: 1971–2010 and for years with high and low indices of the North Atlantic Oscillation and directions of their transformation in various phases of NAODJFM. The paper applied daily flow values from the period 1971–2010 for 516 stations located on 280 Polish rivers. In the examined time scales, five types of regime were designated including rivers characterised by a similar distribution and range of monthly runoff values in an average annual cycle. The designated groups, however, differ in terms of the number of rivers, which affects the image of spatial distribution of rivers representing the identified types of regime. The analysis shows that in the studied NAODJFM phases, transformations of the flow regime of many rivers in Poland are often observed. Compared to average conditions (1971–2010), in the negative phase of NAODJFM, the most stable is nival type well formed. The most common transformations relate to the nival regime moderately formed, which usually changes into a nival well formed or nival-pluvial regime. In the positive phase of NAODJFM, regime transformations are more frequent. The most stable type of regime is again nival well formed, and the most common transformation occurs in the case of the pluvio-nival regime (into the nival-pluvial regime) and nival-pluvial regime, which is transformed into well or moderately formed nival regimes.
    Źródło:
    Badania Fizjograficzne Seria A - Geografia Fizyczna; 2018, 9(69); 249-261
    2081-6014
    Pojawia się w:
    Badania Fizjograficzne Seria A - Geografia Fizyczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Curve Flow-duration-Frequency. The flood modelling regime of the Wadi Mazafran catchment in the north of Algeria
    Autorzy:
    Kourat, Sofiane
    Touaibia, Bénina
    Yahiaoui, Abdelhalim
    Powiązania:
    https://bibliotekanauki.pl/articles/2174334.pdf
    Data publikacji:
    2022
    Wydawca:
    Instytut Technologiczno-Przyrodniczy
    Tematy:
    duration
    flood
    flood regime
    flow
    Flow-duration-Frequency modelling
    QdF modelling
    frequency
    Mazafran
    Opis:
    Synthetic modelling of the flood regime is based on the overall knowledge of the hydrological regime in a catchment. The Flow-duration-Frequency (QdF) modelling is used to combine three parameters characterising flood with its mean or exceeded flow, its characteristic duration, and occurrence frequency. Which of these can be established locally at the extreme mean volume flow rates of a catchment reference hydrometric station? The determination of the reference QdF model in mean (volume) and exceeded flows requires two characteristics reflecting the flood regime in a catchment. The first is the characteristic flood duration and the second is the 10-year quantile of the annual maximum instantaneous flow. The comparison of the local situation to the reference QdF models enables to develop the final QdF model of the catchment and therefore the baseline QdF for exceeded and synthetic mono-frequency hydrographs. These are essential components in the study of flood risk mapping and the estimation of the instantaneous peak distribution from mean daily streamflow series.
    Źródło:
    Journal of Water and Land Development; 2022, 54; 121--130
    1429-7426
    2083-4535
    Pojawia się w:
    Journal of Water and Land Development
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of the degree of extremality of high-water flows in selected rivers in Poland in 1971-2006
    Autorzy:
    Nowicka, Barbara
    Mikulska, Małgorzata
    Powiązania:
    https://bibliotekanauki.pl/articles/2034235.pdf
    Data publikacji:
    2010-06-01
    Wydawca:
    Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
    Tematy:
    extreme flood
    threshold values
    standardized flow-duration curve
    hydrological regime
    Opis:
    The paper presents the results of estimation and comparison of risk of extreme floods on rivers of various hydrological regime. The hypothesis that extreme events occur with the same frequency in all rivers was rejected. The limit between extreme and common floods on 30 rivers from different geographical regions of Poland was defined on the basis of standardized flow-duration curve in 1971-2006. These analyses resulted in designing five curve groups. Four measures of flood magnitude have been proposed. The time distribution of extreme events during the last decades was estimated for the most dynamic rivers.
    Źródło:
    Miscellanea Geographica. Regional Studies on Development; 2010, 14; 169-176
    0867-6046
    2084-6118
    Pojawia się w:
    Miscellanea Geographica. Regional Studies on Development
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Water Retention Problem in the Mountain Areas: a Case of Sola River Flows, Polish Carpathians
    Autorzy:
    Jaguś, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/124707.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    mountain river
    river flow
    river regime
    surface runoff
    water retention
    Opis:
    The paper considers mountain rivers, which usually feature high dynamics of hydrological phenomena. The variability of the Sola river flows in the Polish Carpathians is presented based on water-gauge measurements from the hydrological long-period of 1956-2015. The flows for the upper section of the river, where no storage reservoirs are found, were analysed. A broad range of flows was shown – from 0.59 to 1250 m3/s at a mean flow of 15.5 m3/s. It was also shown that within a year, the flows grow in the spring (thaw freshets) and summer periods (rainwater freshets). Mainly the summer freshets are dangerous, consisting in a sudden rise of the flow due to rains. This is shown by the high values of maximum flows in June and July. In the case of mountain rivers, such as the Sola river, it is necessary to undertake the actions stabilising the flows, which on the one hand have flood-prevention importance, and on the other hand protect the water resources in long dry periods. The actions should be concentrated on the proper arrangement of the catchment area, slowing down the rainwater outflow. Appropriate land use is especially important (distribution of forests, of arable and developed areas) depending on the land elevation above the sea level and inclination, as well as creation of small storage facilities.
    Źródło:
    Journal of Ecological Engineering; 2019, 20, 11; 167-177
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Role of Subaquatic Springs in the Formation of Flow, Temperature and Chemical Composition of River Water in the Reserve
    Autorzy:
    Vaganov, Sergey
    Blinov, Sergey
    Belkin, Pavel
    Perevoshchikov, Roman
    Powiązania:
    https://bibliotekanauki.pl/articles/2068457.pdf
    Data publikacji:
    2022
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    karst
    groundwater
    surface water
    subaquatic spring
    chemical composition
    river flow formation
    temperature regime
    nature reserve
    Opis:
    A study of the effect of subaquatic discharge of karst groundwater sources on the composition of the Vishera River, the largest tributary of the Kama River, was carried out. The study was carried out on the territory of the State Nature Reserve "Vishersky" and included the determination of the flow rate, temperature as well as chemical composition of natural waters. Six zones of karst groundwater discharge and their influence on the water regime of the Vishera river were studied in detail. It was shown that subaquatic sources in the places of their discharge, forming up to 36% of the river flow, significantly affect the temperature regime. A significant part of dissolved substances, primarily calcium ions and hydrocarbonate ions, as well as some trace elements (Li, Sr, V, Cr) enter the Vishery river with karst waters. The results of the study show that monitoring the composition and properties of groundwater discharged covertly in the river channel is an important part of the monitoring of water bodies of both protected and developed areas.
    Źródło:
    Journal of Ecological Engineering; 2022, 23, 3; 39--48
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Anthropogenic and Climatic Causality of Changes in the Hydrological Regime of the Dnieper River
    Autorzy:
    Pichura, Vitalii Ivanovich
    Potravka, Larisa Aleksandrovna
    Skrypchuk, Petro Mikhalovich
    Stratichuk, Natalia Vladimirovna
    Powiązania:
    https://bibliotekanauki.pl/articles/124640.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    water regime
    river flow
    Dnieper River
    retrospective analysis
    multivariate statistics
    Wavelet analysis
    Holt-Winters method
    prediction
    Opis:
    The intensive use of water resources and the transformation of natural landscapes under the influence of human economic activity have led to changes in the natural water balance of river drainage basins. The negative processes thereof are intensified by climatic changes that have significantly disturbed the hydrological regime, determined by changes in water content and river flow dynamics. The retrospective study and prediction of the flow of the Dnieper River was carried out using multivariate statistics and adaptive methods of nonlinear time series analysis. The anomalous features were identified and the main periods of changes in the water regime of the river for 190 years (1818–2008) were determined using the standard root-mean-square deviation and wavelet analysis. As a result of non-linear prediction, it was determined that if the tendency of anthropogenic and climatic formation of the water regime of the Dnieper River sustains, there is a 90% probability of insignificant but steady trend and cyclical reduction of the average annual flow by 1.6 m3/s per year to 1120 ± 270 m3/s by 2040. The results of the detailed retrospective analysis for 190 years and the prediction of the probability of changes in the flow of the Dnieper river confirm the previous conclusions of many scientists regarding the significant transformation of the ecosystem of the transboundary river and provide new knowledge regarding the main stages of formation of the water regime and the probability of further regulation of the flow of the Dnieper river if the current conditions of the negative impact of economic activities are maintained in the transboundary basin.
    Źródło:
    Journal of Ecological Engineering; 2020, 21, 4; 1-10
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Heat transfer study from square cylinder immersed in water-based nanofluid: Effect of orientation
    Autorzy:
    Kaur, Jaspinder
    Ratar, Jatinder Kumar
    Tiwari, Anurag Kumar
    Powiązania:
    https://bibliotekanauki.pl/articles/2173435.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    inclined square cylinder
    nanofluids
    Reynolds number
    Prandtl number
    steady flow
    regime
    nanopłyn
    liczba Reynoldsa
    liczba Prandtla
    przepływ stały
    Opis:
    Heat transfer study from the heated square cylinder at a different orientation angle to the stream of nanofluids has been investigated numerically. CuO-based nanofluids were used to elucidate the significant effect of parameters: Reynolds number (1–40), nanoparticle volume fraction (0.00–0.05), the diameter of the NPs (30–100 mn) and the orientation of square cylinder (0–90). The numerical results were expressed in terms of isotherm contours and average Nusselt number to explain the effect of relevant parameters. Over the range of conditions, the separation of the boundary layers of nanofluids increased with the size of the NPs as compared to pure water. NPs volume fraction and its size had a significant effect on heat transfer rate. The square cylinder of orientation angle (45) gained a more efficient heat transfer cylinder than other orientation angles. Finally, the correlations were developed for the average Nusselt number in terms of the relevant parameters for 45 orientation of the cylinder for new applications.
    Źródło:
    Chemical and Process Engineering; 2022, 43, 2; 243--250
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulation of the soil water regime for grassland irrigation
    Autorzy:
    Olszta, W.
    Glinski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/24667.pdf
    Data publikacji:
    1995
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    hydraulic conductivity
    soil profile
    grassland
    moisture retention
    Polska
    crop production
    evapotranspiration
    water regime
    water flow
    climate
    irrigation
    GRAGRO model
    Źródło:
    International Agrophysics; 1995, 09, 2
    0236-8722
    Pojawia się w:
    International Agrophysics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rozpoznawanie wpływu zmiennych parametrów przepływów w rozmywanych korytach rzek na projektowanie budowli hydrotechnicznych
    Modeling deterioration and degradation of water headworks infrastracture assets
    Autorzy:
    Naprawa, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/40963.pdf
    Data publikacji:
    2017
    Wydawca:
    Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
    Tematy:
    koryta rzeczne
    rezim rzeki
    przeplyw wody
    erozja
    sedymentacja
    budowle hydrotechniczne
    zalozenia projektowe
    riverbed
    river regime
    water flow
    erosion
    sedimentation
    hydrotechnical construction
    design
    Źródło:
    Acta Scientiarum Polonorum. Architectura; 2017, 16, 3
    1644-0633
    Pojawia się w:
    Acta Scientiarum Polonorum. Architectura
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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