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(Schaden beim Einsatz keramischer Werkstoffe im Tribosystem mit Wasser) (Cavitation caused damage of ceramic materials in tribological contact with water lubrication)
ANNUAL LITERATURE SURVEY 1996 119 adopting Richard's assumption, a three-phase flow model is introduced with capillary heads of the water and the oil as variables. The resulting model which is coupled and strongly non-linear is solved using a vertical twodimensional finite-element procedure together with a quasi-Newton optimization algorithm. Various scenarios of oil migration in the unsaturated and the capillary zone were simulated. In particular, the dynamics of the water and oil phases during the migration process is discussed. (from Authors)
(Schaden beim Einsatz keramischer Werkstoffe im Tribosystem mit Wasser) (Cavitation caused damage of ceramic materials in tribological contact with water lubrication) Franke H.-J., Fritsch J. & Lachmayer R., Tribologie undSchmierungstechnik, 1996, 43/1 (40-42). In German. The importance of environment safety leads to an increasing number of water lubricated machine parts. In this context bearings and seals made of ceramic materials are often an innovative solution with good performance. But experimental observation and theory show, that as soon as the boiling point of the lubricant is reached and two phase phenomena arise, completely different behaviour of a device may occur. Two cases are discussed, dealing with the performance of mating rings for mechanical seals and Si3 N4 roller bearings mounted in magnetic couplings. (from English summary) Modelling the Bagnold stress effects in vertical slurry flow Bartosik A.S., Vodohospodarsky Casopis/Journal of Hydrology & Hydrornechanics, 1996, 44/1 (49-58). In English. The Bagnold hypothesis has been used to construct a mathematical model for fully developed turbulent slurry flow in a vertical pipe. In the mathematical model the total shear stress is modelled as the sum of liquid-wall and particle-wall stresses. The particle-wall stress is described by a modified Bagnold function. Predictions of frictional headloss for slurries are compared with experimental data obtained for two different pipe diameters. The slurries contains water and coarse particles and the smallest and highest median particle diameter was 1.5 and 3.4 mm respectively. Comparison between predicted and measured data are made for solids concentration up to 45*/, by volume and for solid/liquid density ratio between 1.04 and 2.65. (from Author)
Modelling the Bagnold stress effects in vertical slurry flow Bartosik A.S., Vodohospodarsky Casopis/Journal of Hydrology & Hydromechanics, 1996, 44/1 (49-58). In English. The Bagnold hypothesis has been used to construct a mathematical model for fully developed turbulent slurry flow in a vertical pipe. In the mathematical model the total shear stress is modelled as the sum of liquid-wall and particle-wall stresses. The particle-wall stress is described by a modified Bagnold function. Predictions of frictional headloss for slurries are compared with experimental data obtained for two different pipe diameters. The slurries contains water and coarse particles and the smallest and highest median particle diameter was 1.5 and 3.4 mm respectively. Comparison between predicted and measured data are made for solids concentration up to 45% by volume and for solid/liquid density ratio between 1.04 and 2.65. (from Author) Mnltiphase approach to the numerical solution of a sharp interface saltwater intrusion problem Huyakorn P.S., Yu Y.S. & Park N.S., Water Resources Research, 1996, 32/1 (93-102). In English. A sharp interface numerical model is developed to simulate saltwater intrusion in multilayered coastal aquifer systems. The model takes into account the flow dynamics of salt water and fresh water assuming a sharp interface between the two liquids. In contrast to previous two-fluid flow models which were formulated using the hydraulic heads of fresh water and salt water as the dependent variables, the present model employs a mixed formulation having one fluid potential and a pseudosaturation as the dual dependent variables. Conversion of the usual sharp interface flow equations for each aquifer to an equivalent set of two-phase flow equations leads to the definitions of pseudosaturation, capillary pressure, and constitutive relations. The desired governing .equations are then obtained by connecting neighb oring aquifers via vertical leakage. The proposed formulation is based on a Galerkin finite element discretization. The numerical solution incorporates upstream weighting and nonlinear algorithms with several enhanced features, including rigorous treatment ofaquitard leakage and well conditions, and a robust Newton-Raphson procedure with automatic time stepping. (from Authors)
A finite volume Eulerian-Lagrangian localized adjoint method for solution of the contaminant transport equations in two-dimensional muitiphase flow systems Binning P. & Celia M.A., Water Resources Research, 1996, 32/1 (103-114). In English. An Eulerian-Lagrangian localized adjoint method (ELLAM) numerical solution is described for the multiphase contaminant transport equations in two dimensions. The ELLAM uses finite volume test functions in the space-time domain defined by the characteristics of the hyperbolic part of the governing equation. Combination of the finite volume test functions with the conservative form of the governing equation results in a local conservation of mass property. A combined conservative/noneonservative ELLAM is developed with an ELLAM formulation based on the nonconservative form of the governing equation being applied to subdomains intersecting first-type boundaries and a conservative ELLAM being used for all other subdomains. The combined conservative/nonconservative ELLAM is compared to a Galerkin finite element scheme and is found to have greatly superior performance, requiring far fewer time steps to obtain a solution ofequivalent accuracy. (from Authors) A finite volume Eulerian-Lagrangian localized adjoint method for solution of the contaminant transport equations in two-dimensional multiphase flow systems Binning P. & Celia M.A., Water Resources Research, 1996, 32/1 (103-114). In English. An Eulerian-Lagrangian localized adjoint method (ELLAM) numerical solution is described for the multiphase contaminant transport equations in two dimensions. The ELLAM uses finite volume test functions in the
(Schaden beim Einsatz keramischer Werkstoffe im Tribosystem mit Wasser) (Cavitation caused damage of ceramic materials in tribological contact with water lubrication) Franke H.-J., Fritsch J. & Lachmayer R., Tribologie undSchmierungstechnik, 1996, 43/1 (40-42). In German. The importance of environment safety leads to an increasing number of water lubricated machine parts. In this context bearings and seals made of ceramic materials are often an innovative solution with good performance. But experimental observation and theory show, that as soon as the boiling point of the lubricant is reached and two phase phenomena arise, completely different behaviour of a device may occur. Two cases are discussed, dealing with the performance of mating rings for mechanical seals and Si3 N4 roller bearings mounted in magnetic couplings. (from English summary) Modelling the Bagnold stress effects in vertical slurry flow Bartosik A.S., Vodohospodarsky Casopis/Journal of Hydrology & Hydrornechanics, 1996, 44/1 (49-58). In English. The Bagnold hypothesis has been used to construct a mathematical model for fully developed turbulent slurry flow in a vertical pipe. In the mathematical model the total shear stress is modelled as the sum of liquid-wall and particle-wall stresses. The particle-wall stress is described by a modified Bagnold function. Predictions of frictional headloss for slurries are compared with experimental data obtained for two different pipe diameters. The slurries contains water and coarse particles and the smallest and highest median particle diameter was 1.5 and 3.4 mm respectively. Comparison between predicted and measured data are made for solids concentration up to 45*/, by volume and for solid/liquid density ratio between 1.04 and 2.65. (from Author)
Modelling the Bagnold stress effects in vertical slurry flow Bartosik A.S., Vodohospodarsky Casopis/Journal of Hydrology & Hydromechanics, 1996, 44/1 (49-58). In English. The Bagnold hypothesis has been used to construct a mathematical model for fully developed turbulent slurry flow in a vertical pipe. In the mathematical model the total shear stress is modelled as the sum of liquid-wall and particle-wall stresses. The particle-wall stress is described by a modified Bagnold function. Predictions of frictional headloss for slurries are compared with experimental data obtained for two different pipe diameters. The slurries contains water and coarse particles and the smallest and highest median particle diameter was 1.5 and 3.4 mm respectively. Comparison between predicted and measured data are made for solids concentration up to 45% by volume and for solid/liquid density ratio between 1.04 and 2.65. (from Author) Mnltiphase approach to the numerical solution of a sharp interface saltwater intrusion problem Huyakorn P.S., Yu Y.S. & Park N.S., Water Resources Research, 1996, 32/1 (93-102). In English. A sharp interface numerical model is developed to simulate saltwater intrusion in multilayered coastal aquifer systems. The model takes into account the flow dynamics of salt water and fresh water assuming a sharp interface between the two liquids. In contrast to previous two-fluid flow models which were formulated using the hydraulic heads of fresh water and salt water as the dependent variables, the present model employs a mixed formulation having one fluid potential and a pseudosaturation as the dual dependent variables. Conversion of the usual sharp interface flow equations for each aquifer to an equivalent set of two-phase flow equations leads to the definitions of pseudosaturation, capillary pressure, and constitutive relations. The desired governing .equations are then obtained by connecting neighb oring aquifers via vertical leakage. The proposed formulation is based on a Galerkin finite element discretization. The numerical solution incorporates upstream weighting and nonlinear algorithms with several enhanced features, including rigorous treatment ofaquitard leakage and well conditions, and a robust Newton-Raphson procedure with automatic time stepping. (from Authors)
A finite volume Eulerian-Lagrangian localized adjoint method for solution of the contaminant transport equations in two-dimensional muitiphase flow systems Binning P. & Celia M.A., Water Resources Research, 1996, 32/1 (103-114). In English. An Eulerian-Lagrangian localized adjoint method (ELLAM) numerical solution is described for the multiphase contaminant transport equations in two dimensions. The ELLAM uses finite volume test functions in the space-time domain defined by the characteristics of the hyperbolic part of the governing equation. Combination of the finite volume test functions with the conservative form of the governing equation results in a local conservation of mass property. A combined conservative/noneonservative ELLAM is developed with an ELLAM formulation based on the nonconservative form of the governing equation being applied to subdomains intersecting first-type boundaries and a conservative ELLAM being used for all other subdomains. The combined conservative/nonconservative ELLAM is compared to a Galerkin finite element scheme and is found to have greatly superior performance, requiring far fewer time steps to obtain a solution ofequivalent accuracy. (from Authors) A finite volume Eulerian-Lagrangian localized adjoint method for solution of the contaminant transport equations in two-dimensional multiphase flow systems Binning P. & Celia M.A., Water Resources Research, 1996, 32/1 (103-114). In English. An Eulerian-Lagrangian localized adjoint method (ELLAM) numerical solution is described for the multiphase contaminant transport equations in two dimensions. The ELLAM uses finite volume test functions in the