In this paper, we extend the applications of proper orthogonal decomposition （POD） method, i.e., apply POD method to a mixed finite element （MFE） formulation naturally satisfied Brezz-Babu^ka for parabolic equatio...In this paper, we extend the applications of proper orthogonal decomposition （POD） method, i.e., apply POD method to a mixed finite element （MFE） formulation naturally satisfied Brezz-Babu^ka for parabolic equations, establish a reduced-order MFE formulation with lower dimensions and sufficiently high accuracy, and provide the error estimates between the reduced-order POD MFE solutions and the classical MFE solutions and the implementation of algorithm for solving reduced-order MFE formulation. Some numerical examples illustrate the fact that the results of numerical computation are consis- tent with theoretical conclusions. Moreover, it is shown that the new reduced-order MFE formulation based on POD method is feasible and efficient for solving MFE formulation for parabolic equations.展开更多
The oil-film oscillation in dimensional nonlinear problem. In this a large rotating machinery is a complex high- paper, a high pressure rotor of an aero engine with a pair of liquid-film lubricated bearings is modeled...The oil-film oscillation in dimensional nonlinear problem. In this a large rotating machinery is a complex high- paper, a high pressure rotor of an aero engine with a pair of liquid-film lubricated bearings is modeled as a twenty-two-degree-of-freedom nonlinear system by the Lagrange method. This high-dimensional nonlinear system can be reduced to a two-degree-of-freedom system preserving the oil-film oscillation property by introducing the modified proper orthogonal decomposition （POD） method. The effi- ciency of the method is shown by numerical simulations for both the original and reduced systems. The Chen-Longford （C-L） method is introduced to get the dynamical behaviors of the reduced system that reflect the natural property of the oil-film oscillation.展开更多
Gas-oil-water three phase flow is of practical significance in oil and gas industries. An insight into the dynamics of such multiphase flows is significantly valuable to obtain optimal design parameters and operationa...Gas-oil-water three phase flow is of practical significance in oil and gas industries. An insight into the dynamics of such multiphase flows is significantly valuable to obtain optimal design parameters and operational conditions. Since flow patterns are sensitive to pipe geometry, flow conditions and thermophysical properties of fluid, it is extremely challenging to provide a universal solution for visualisation of three phase horizontal flows. This study deals with a fully developed, turbulent three phase flow and presents the outcomes of electrical tomographic imaging techniques to visualise gas-oil-water flows in a horizontal pipeline.展开更多
基金supported by the National Science Foundation of China(11271127 and 11061009)Science Research Program of Guizhou(GJ[2011]2367)the Co-Construction Project of Beijing Municipal Commission of Education
文摘In this paper, we extend the applications of proper orthogonal decomposition （POD） method, i.e., apply POD method to a mixed finite element （MFE） formulation naturally satisfied Brezz-Babu^ka for parabolic equations, establish a reduced-order MFE formulation with lower dimensions and sufficiently high accuracy, and provide the error estimates between the reduced-order POD MFE solutions and the classical MFE solutions and the implementation of algorithm for solving reduced-order MFE formulation. Some numerical examples illustrate the fact that the results of numerical computation are consis- tent with theoretical conclusions. Moreover, it is shown that the new reduced-order MFE formulation based on POD method is feasible and efficient for solving MFE formulation for parabolic equations.
基金Project supported by the National Natural Science Foundation of China (No. 11072065)
文摘The oil-film oscillation in dimensional nonlinear problem. In this a large rotating machinery is a complex high- paper, a high pressure rotor of an aero engine with a pair of liquid-film lubricated bearings is modeled as a twenty-two-degree-of-freedom nonlinear system by the Lagrange method. This high-dimensional nonlinear system can be reduced to a two-degree-of-freedom system preserving the oil-film oscillation property by introducing the modified proper orthogonal decomposition （POD） method. The effi- ciency of the method is shown by numerical simulations for both the original and reduced systems. The Chen-Longford （C-L） method is introduced to get the dynamical behaviors of the reduced system that reflect the natural property of the oil-film oscillation.
基金the European Metrology Research Programme (EMRP) project “Multiphase flow metrology in the Oil and Gas production” which is jointly funded by the European Commission and participating countries within Euramet and the European Union
文摘Gas-oil-water three phase flow is of practical significance in oil and gas industries. An insight into the dynamics of such multiphase flows is significantly valuable to obtain optimal design parameters and operational conditions. Since flow patterns are sensitive to pipe geometry, flow conditions and thermophysical properties of fluid, it is extremely challenging to provide a universal solution for visualisation of three phase horizontal flows. This study deals with a fully developed, turbulent three phase flow and presents the outcomes of electrical tomographic imaging techniques to visualise gas-oil-water flows in a horizontal pipeline.
