Wyniki wyszukiwania - Biblioteka Nauki

1

Hydrodynamics of the Vistula estuary: measurements and modelling

100%

Robakiewicz M. , Jasińska E.

Oceanological Studies

|

1998

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tom Vol. 27, No. 3

83-93

EN

Development of measuring techniques enabled execution of detailed in situ measurements in the maritime part of the Vistula estuary. The data gathered were then used for verification of a three-dimensional model. In situ measurements of hydrodynamic conditions (magnitude and direction of water currents, salinity, temperature) were carried out in autumn 1995 as short-term and long-term registrations. Calculations done by the numerical model, based on collected hydro-meteorological data, agree well with short-term registrations. The influence of the forcing functions and numerical coefficients on the results of modelling are discussed.

2

Microphytobenthic primary production on exposed coastal sandy sediments of the Southern Baltic Sea using ex situ sediment cores and oxygen optodes

80%

Kuriyama K. , Gründling-Pfaff S. , Diehl N. , Woelfel J. , Karsten U.

Oceanologia

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2021

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tom No. 63 (2)

247--260

EN

The shallow coastal water zone of the tide-less southern Baltic Sea is dominated by exposed sandy sediments which are typically inhabited by microphytobenthic communities, but their primary production is poorly studied, and hence four stations between 3.0 and 6.2 m depth were investigated. Sediment cores were carefully taken to keep the natural layering and exposed in a controlled self-constructed incubator. Respiratory oxygen consumption and photosynthetic oxygen production were recorded applying planar oxygen optode sensors. We hypothesized that with increasing water depths the effects of wind- and wave-induced erosion and mixing of the upper sediment layer are dampened and expected higher microphytobenthic biomass and primary production in the incubated cores. Our data partly confirm this hypothesis, as cores sampled at the most exposed stations contained only 50% chlorophyll a m−2 compared to the deeper stations. However, primary production was highly variable, probably due to fluctuating sediment-disturbing conditions before the cores were taken. Due to these physical forces sand grains were highly mobile and rounded, and small epipsamic benthic diatoms dominated, which preferentially occurred in some cracks and crevices as visualized by scanning electron microscopy. The data fill an important gap in reliable production data for sandy sediments of the southern Baltic Sea, and point to the ecological importance and relevant contribution of microphytobenthic communities to the total primary production of this marine ecosystem. Oxygen planar optode sensor spots proved to be a reliable, sensitive and fast detection system for ex situ oxygen exchange measurements in the overlying water of intact sediment cores.

3

Hydrodynamic modelling in the Polish Zone of the Baltic Sea - an overview of Polish achievements

80%

Jasińska E. , Robakiewicz M. , Staśkiewicz A.

Oceanologia

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2003

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tom No. 45 (1)

107-120

EN

This paper gives a general overview of Polish experience and achievements with regard to hydrodynamic modelling in the Polish zone of the Baltic Sea. The first work started already at the end of the sixties when the first 1D and 2D hydrodynamic models were set up. With the development of numerical methods and increasing computational power a number of 1D, 2D and 3D models were set up and tested. Global, regional and local models cover the most important water bodies, i.e. the Pomeranian Bay - Szczecin Lagoon and Gulf of Gdansk - Vistula Lagoon systems.

4

Seepage process on weathered crust elution-deposited rare earth ores with ammonium carboxylate solution

80%

Zou H. , Zhang Z. , Chen Z. , Liu D. , Chai X. , Zhang H. , Chi R.-a.

Physicochemical Problems of Mineral Processing

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2020

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tom Vol. 56, iss. 1

89--101

EN

In order to reveal the seepage law of ammonium carboxylate solution in the in-situ leaching process of weathered crust elution-deposited rare earth ores, the effects of concentration, pH, temperature, particle size and porosity on permeability were discussed in this paper. The results shown that the seepage of the leaching agent solutions in the rare earth ore follows Darcy's law and displays a laminar flow under the conditions of this experiment and seepage velocity can be increased by changing leaching conditions. The permeability coefficients are inversely proportional to concentrations of ammonium acetate, ammonium tartrate and ammonium citrate whose concentration is greater than 0.7wt%, because the insoluble complexes formed by the reaction of ammonium citrate with RE3+ at lower concentration n decrease the permeability coefficient. The permeability coefficients of ammonium carboxylate solutions increase firstly and then decrease with the pH increased. The maximum of permeability coefficients of ammonium acetate, ammonium tartrate and ammonium citrate solution were 2.92, 1.91 and 2.70, respectively, while the pH of solution were 5, 6 and 7, respectively. Increasing temperature is beneficial for the seepage of ammonium carboxylate solution in orebody, therefore, it is helpful for leaching operation in summer. Moreover, clay minerals particle size and porosity are the key factors affecting the permeability of ammonium carboxylate solution in orebody. The permeability coefficients of ammonium acetate, ammonium tartrate and ammonium citrate solutions are 2.92×104cm/s,1.90×10-4cm/s and 2.69×10-4cm/s, respectively, at the same temperature of 293K, original particle size and porosity of the ore. Ammonium acetate solution has the best permeability in orebody.

5

Universal velocity profile for bubbly flow in the boundary layer

80%

Mikielewicz D.

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tom Vol. 21, nr 3-4

117-132

EN

In the work presented is a new approach to modelling the bubble flow in a boundary layer. The approach is based on summation of the dissipation energy coming from the shearing turbulent flow in the absence of bubbles and the dissipation contribution from the bubble motion. As a result we obtain the shear stress of equivalent single phase turbulent flow. An approximate solution to the model has been given in a form of an explicit differential equation, which can be solved with assumption of constant or variable void fraction distribution. Velocity distributions calculated using the new model have been compared against the experimental data of turbulent bubble flows with small void fraction. A good consistency of calculations performed using a new model with experiment has been obtained.

6

Application of two coastal profile evolution models to Lubiatowo, Poland and La Barrosa, Spain

80%

O'Hare T. J. , Ostrowski R. , Emsley S. M. , Huntley D. A.

Archives of Hydro-Engineering and Environmental Mechanics

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2006

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tom Vol. 53, nr 3

235-266

EN

Two contrasting coastal profile models are applied to three bathymetries including a uniform gradient beach and natural profiles (multi-barred and multi-stepped) obtained from Lubiatowo, Poland and La Barrosa, Spain. The first model, developed at the Institute of Hydro-Engineering of the Polish Academy of Science (IBW PAN) (Poland), couples a quasi-3D model for nearshore hydrodynamics with a quasi-phase resolving sediment transport model which considers transport in the bed load, contact load and outer layers. The second model (PLYMPROF), developed at the University of Plymouth (UK), couples a relatively simple wave transformation model with a new abstracted description of cross-shore sediment transport beneath waves. A variety of model simulations are described, including simple runs with uniform wave forcing (up to 50 days in duration using PLYMPROF) and runs with parameterized wave forcing (wave height and wave period in deep water) for periods with one or two storm events (6-11 days total duration). Both models coped well with the different initial profiles and with uniform and time-varying wave conditions. The results of the simulations suggest that onshore-directed sediment transport in the shoaling and outer surf zones is dominant for the cases considered. Compared to the IBW PAN model, the PLYMPROF model results (using coefficients from a separate study of bar evolution at Duck, USA) show larger offshore-directed transport in the inner surf zone associated with return flow, with the overall sediment transport pattern located considerably closer to the shore. Alteration of a single coefficient in the PLYMPROF model shifts the predicted transport pattern seawards, but also results in enhanced offshore-directed transport. Despite differences in predicted cross-shore sediment transport the two models produced surprisingly similar trends in overall profile evolution suggesting that feedback between existing bathymetry and the sediment transport pattern may exert a major control on profile development. Results also suggested that bar migration patterns cannot be simply related to the occurrence or absence of storm conditions, but rather depend more subtly on the exact placement of wave breaking locations in relation to existing bars. Incorporation of tidal water level variations for La Barrosa produced small changes in model predictions, with tidal migration of the sediment flux pattern suppressing the development of bar morphology in line with the form of the observed profile.

7

Modelowanie hydrodynamiki trójfazowych reaktorów ze stałym złożem

80%

Burghardt A. , Janecki A. , Bartlemus G.

Inżynieria Chemiczna i Procesowa

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2001

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tom T. 22, z. 3B

307--312

PL

W pracy przedstawiono wyniki doświadczeń i obliczeń, których celem było znalezienie modelu opisującego z dobrą dokładnością hydrodynamikę współprądowego reaktora trójfazowego ze stałym złożem, pracującego w reżimie ciągłego przepływu gazu.

EN

The paper presents the results of experiments and calculations aimed at finding the model that describes hydrodynamics of cocurrent fixed-bed three-phase reactor operating in GCF regime with satisfactory accuracy.

8

Modelling of the hydrodynamics of concurrent gas and liquid flow through packed bed

80%

Janecki D. , Bartelmus G. , Burghardt A.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2016

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tom nr 19(3)

267--284

EN

The aim of the present study is to simulate concurrent gas and liquid flow through packed bed in the gas continuous flow regime (GCF) and continuity shock waves regime(CSW) using computational fluid dynamics (CFD). The application of multiple gas-liquid-solid model requires the knowledge of relationships determining interactions between phases. The exchange coefficients of these forces were defined by means of equations suggested by ATTOU et al. (1999). As a result of the computational simulation the following data were obtained: gas pressure drop in the bed, volume fraction distribution of a given phase (liquid and gas holdups) along the packing and its mean value in the reactor. The comparison of the values of the hydrodynamic parameters, both calculated and obtained experimentally in a column packed with 3 mm glass spheres, indicates that CFD model can be applied to model the hydrodynamics of concurrent gas and liquid flows through a packed bed because a good compatibility of the compared parameters was obtained.

9

Operacje periodyczne jako sposób intensyfikacji procesów w reaktorach trójfazowych ze stałym złożem

80%

Gancarczyk A. , Bartelmus G. , Krótki T.

Przemysł Chemiczny

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2007

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tom T. 86, nr 10

965-967

10

Dilepton creation based on an analytic hydrodynamic solution

80%

Csanád M. , Krizsán L.

Open Physics

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2014

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tom 12

|

nr 2

132-140

EN

High-energy collisions of various nuclei, so called “Little Bangs” are observed in various experiments of heavy ion colliders. The time evolution of the strongly interacting quark-gluon plasma created in heavy ion collisions can be described by hydrodynamical models. After expansion and cooling, the hadrons are created in a freeze-out. Their distribution describes the final state of this medium. To investigate the time evolution one needs to analyze penetrating probes, such as direct photon or dilepton observables, as these particles are created throughout the evolution of the medium. In this paper we analyze an 1+3 dimensional analytic solution of relativistic hydrodynamics, and we calculate dilepton transverse momentum and invariant mass distributions. We investigate the dependence of dilepton production on time evolution parameters, such as emission duration and equation of state. Using parameters from earlier fits of this model to photon and hadron spectra, we compare our calculations to measurements as well. The most important feature of this work is that dilepton observables are calculated from an exact, analytic, 1+3D solution of relativistic hydrodynamics that is also compatible with hadronic and direct photon observables.

11

Ring thruster – a preliminary optimisation study

80%

Matuszewski L.

Polish Maritime Research

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2007

|

tom S 1

67-70

12

Influence of the Gdańsk - east wastewater treatment plant on the coastal zone of the Gulf of Gdańsk - hydrodynamic aspects

80%

Robakiewicz M.

Oceanological Studies

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2000

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tom Vol. 29, No. 4

99-110

EN

The Gdańsk - East Wastewater Treatment Plant (WWTP) with its predicted average discharge of 2 m3 s-1 is the largest treatment plant with an outfall pointing into the Gulf of Gdansk. The discharge of only mechanically treated wastes into the final kilometre of the River Wisla gave rise to serious environmental problems in the coastal zone. This paper discusses the situation in 1995 and the possible relocation of the outfall based on hydrodynamic conditions. Numerical modelling has been applied to estimate the area influenced by treated water discharged at a variety of locations. The analysis indicates that the optimum location for the outfall would be approximately 2500 metres offshore.

13

Wypełnienia kolumn reaktywnych i ich specyficzne charakterystyki hydrodynamiczne

80%

Kołodziej A. , Jaroszyński M. , Bylica I.

Przemysł Chemiczny

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2003

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tom T. 82, nr 8-9

1214-1217

14

Multiphase Flow Mixture In 180° Pipe Bends

80%

Pietrzak M. , Witczak S.

Chemical and Process Engineering

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2013

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tom 34

|

nr 2

227-239

EN

This paper presents the results of research regarding measurements of the values of pressure drops during horizontal flow of gas-liquid and gas-liquid-liquid mixture through 180o pipe bends. The conducted insightful analysis and assessment during multi-phase flow in pipe bends has enabled to develop a new method for determination of their values. This new method for determining pressure drops ensures higher precision of calculation in comparison to other methods presented in literature and can be applied for calculation of these parameters during multi-phase flows in pipe bends with various geometries.

15

Pomiary chropowatości części podwodnej kadłuba a wymagania armatorów

80%

Kania C.

Ochrona przed Korozją

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1998

|

tom nr 1

2-4

PL

W artykule przedstawiono zagadnienia chropowatości części podwodnej kadłuba i jej wpływ na hydrodynamiczną charakterystykę hadłuba. Omówiono budowę i zasadę funkcjonowania przyrządu do pomiaru chropowatości oraz sposób interpretacji wyników. Przytoczono wyniki pomiarów chropowatości części podwodnej kadłuba na przykładzie kilku statków budowanych w polskich stoczniach w ciągu ostatnich kilku lat.

EN

The paper presents problems of hull underwater part roughness and its effect on the hydrodynamics characteristic of a ship hull. Construction and principle of operation of the roughness measuring instrument and a method of results interpretation are described. Results of measurements of hull underwater part roughness on a example of a number of ships huilt in Polish shipyards in the last few years are quoted.

16

An analysis of the mechanism of flow in ice-covered rivers

80%

Meyer Z.

Acta Geophysica

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2010

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tom Vol. 58, no. 2

337-355

EN

The paper presents a mechanism of flow of water in an ice-covered river in the case of movable bottom. The analysis is based upon the principal hydrodynamics equations of turbulent flow in the case of steady uniform motion. It leads to the conclusion of linear distribution of the turbulent shear stress with depth. It allows to obtain the vertical distribution of velocity of flowing water under the assumption that at the boundaries (movable bottom and ice) the viscosity of water is greater than the kinematics viscosity. The relations describing the vertical distribution of velocity of flowing water, as well as the eddy viscosity coefficient under these conditions, are given.

17

Two-dimensional numerical model for tidal motion in the sea

80%

Hung N. B.

Oceanologia

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1978

|

tom 08

18

Equation of state and initial temperature of quark gluon plasma at RHIC

80%

Csanád M. , Májer I.

Open Physics

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2012

|

tom 10

|

nr 4

850-857

EN

In gold-gold collisions of the Relativistic Heavy Ion Collider a perfect fluid of strongly interacting quark gluon plasma (sQGP) is created. The time evolution of this fluid can be described by hydrodynamical models. After an expansion, hadrons are created during the freeze-out period. Their distribution reveals information about the final state. To investigate the time evolution one needs to analyze penetrating probes: e.g. direct photon observations. In this paper we analyze a 1+3 dimensional solution of relativistic hydrodynamics. We calculate momentum distribution, azimuthal asymmetry and momentum correlations of direct photons. Based on earlier fits to hadronic spectra, we compare photon calculations to measurements to determine the equations of state and the initial temperature of sQGP. We find that the initial temperature in the center of the fireball is 507±12 MeV, while for the sound speed we get c s=0.36±0.02. We also estimate a systematic error of these results. We find that the measured azimuthal asymmetry is also compatible with this model. We also predict a photon source that is significantly larger in the out direction than in the side direction.

19

Scaling of flow phenomena in circulating fluidized bed boilers

80%

Mirek P.

Chemical and Process Engineering

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2011

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tom 32

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nr 2

91-100

EN

The paper presents an overview of scaling models used for determining hydrodynamic parameters of Circulating Fluidized Bed boilers. The governing equations and the corresponding dimensionless numbers are derived and presented for three different approaches to the scaling law of fluidized beds: classical dimensional analysis, differential equations and integrated solutions and experimental correlations. Some results obtained with these equations are presented. Finally, the capabilities and limitations of scaling experiments are discussed.

20

The influence of sampling point on solids suspension density applied in scaling of the hydrodynamics of a supercritical CFB boiler

80%

Mirek P. , Ziaja J.

Chemical and Process Engineering

|

2011

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tom 32

|

nr 4

391-399

EN

The article presents the results of laboratory tests carried out on a scaling model of the 966MWth fluidised-bed boiler operating in the Lagisza Power Plant, made on a scale of 1:20 while preserving the geometrical similarity. The tests were carried out for scaled-down material taken from different locations on the circulation contour in the state of full boiler loading. To reflect the hydrodynamic conditions prevailing in the combustion chamber, solids with properly selected density and particle size distribution were used. The obtained results have made it possible to determine the location for taking the most representative granular material sample.