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1
Content available JMATRIX - package for relativistic J-MATRIX calculations in elastic scattering of electrons from model potentials
Syty P., Sienkiewicz J. E.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2017
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Vol. 21, No 1
17--42
EN
We present a software package JMATRIX, consisting of two computer codes written in FORTRAN 95 and parallelized with OpenMP, implementing the so-called J-matrix method, applied to elastic scattering of electrons on the radial potential, vanishing faster than the Coulomb potential. In the J-matrix method, the physical scattering problem is replaced by using a well-defined model which is solved analytically. The presented software implements both non-relativistic and relativistic versions of the method, and allows calculations of scattering phase shifts as well as cross sections, in cases when the scattering potential is given through an analytical formula. We performed test calculations for the scattering potential modeled as a truncated Coulomb potential. We show that the numerical phase shifts to converge as we increase the size of the basis used to truncate the scattering potential, and that the method is suitable for calculating the total differential momentum transfer and spin polarization cross sections, using the partial-wave analysis.
2
Content available Numerical analysis of momentum transfer processes in a mechanically agitated air – biophase – liquid system
Musiał M., Cudak J., Karcz J.
Chemical and Process Engineering
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2017
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Vol. 38, nr 3
465--475
EN
The results of numerical computations concerning momentum transfer processes in an air – biophase – liquid system agitated in a bioreactor equipped with baffles and a Smith turbine (CD 6 impeller) are presented in this paper. The effect of sucrose concentration on the distributions of the velocity of the continuous phase, gas hold-up and the size of gas bubbles in the system was analysed. Simulation results were presented in the form of the contours of the analysed magnitudes. The effect of sucrose concentration on the averaged values (i.e. determined on the basis of local values) of gas hold-up and gas bubbles size was evaluated. The results of the numerical computations of gas hold-up were compared with our own experimental data.
3
Content available remote Momentum transfer in an agitated vessel equipped with an eccentrically located he 3 impeller
Cudak M., Karcz J.
Chemical and Process Engineering
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2008
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Vol. 29, z. 4
1071-1082
EN
Local momentum transfer process in the region of the wall has been analysed in an agitated vessel equipped with an eccentrically located HE 3 impeller of the diameter d = 0.5D. The effect of the impeller eccentricity on the axial and angular profiles of the momentum transfer coefficients has been studied within the turbulent regime of the Newtonian liquid flow in an unbaffled agitated vessel. The local and averaged momentum transfer coefficients have been correlated by means of suitable equations (6) - (14).
PL
Analizowano lokalne wartości współczynników przenoszenia pędu w obszarze przyściennym mieszalnika z niecentrycznie umieszczonym mieszadłem HE 3 o średnicy d = 0,5D. Zbadano wpływ położenia mieszadła na osiowe i kątowe profile współczynników przenoszenia pędu w zakresie burzliwego przepływu cieczy newtonowskiej w mieszalniku bez przegród. Wyniki badań lokalnych i uśrednionych współczynników przenoszenia pędu aproksymowano odpowiednimi równaniami.
4
Content available remote Interface between turbulent flows above and within rough porous walls
Pokrajac D., Manes C.
Acta Geophysica
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2008
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Vol. 56, no. 3
824-844
EN
This paper explores the concept of a macroscopic boundary between turbulent flows above and within rough permeable walls. The macroscopic boundary and the associated conditions for macroscopic flow variables have been thoroughly investigated for laminar, but not for turbulent flows. The literature on laminar flows follows two main conceptual models of the boundary: sharp boundary with step changes in macroscopic variables and gradual boundary with smooth changes of variables. The former approach is usually associated with the two-domain simulation models and the latter one with the single-domain models. This paper presents the derivation of the step conditions for velocity and shear stress at the macroscopic boundary between turbulent boundary layer and turbulent porous media flows. The physical meaning of the main terms in the shear stress condition is discussed in order to clarify the relationship between two-domain and single-domain simulation models.
5
Content available remote Flow behaviour of ice slurry - experimental investigation
Niezgoda-Żelasko B.
Transactions of the Institute of Fluid-Flow Machinery
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2006
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nr 118
71-89
EN
The paper presents results of studies on ice slurry flows through horizontal tubes. The possibility of treating rheological parameters of ice slurry as being those of a kind of Bingham fluid was confirmed. The values of parameters (mass fraction, flow velocity) corresponding to laminar, intermediate and turbulent flow, were determined. This permits to optimize the flow in the systems working with ice slurries. The work includes a comparison of experimental results with computational methods of determining pressure drops for a Bingham fluid over laminar (the Hedstrom method) and turbulent (the Tomita method) ranges. A verification, based on author's experimental results, of the Fanning and Blasius expression for the Fanning friction factor of ice slurry became possible by introducing the dimensionless generalised Reynolds number. In the last part of the paper the issues connected with the criteria for transition of ice slurry from laminar to turbulent flow are discussed.
6
Experimental investigation of momentum and heat transfer phenomena in ice slurry flow
Niezgoda-Żelasko B., Zalewski W., Żelasko J.
Turbulence : international journal
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2005
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Vol. 11
133-140
EN
The article presents experimental results for momentum and heat transfer which occur during an ice slurry flow. The ice slurry studied was formed on the basis of a 10.6% ethanol water solution. The obtained results enabled to assign appropriate computational models to the processes under study and to determine friction factors and heat transfer coefficients. This will help engineers in the design of installations operating with ice slurries. Establishing of dependencies between pressure drop and heat transfer coefficient, and between flow velocity and ice content will make it possible to optimize the selection of geometric and flow parameters of installations using ice slurry as a coolant
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