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Paul Vigneaux - One of the best experts on this subject based on the ideXlab platform.
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On Stability Condition for bifluid flows with surface tension : application to microfluidics
Journal of Computational Physics, 2008Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:Models for incompressible immiscible bifluid flows with surface tension are here considered. Since Brackbill, Kothe and Zemach (J. Comput. Phys. 100, pp 335-354, 1992) introduced the Continuum Surface Force (CSF) method, many methods involved in interface tracking or capturing are based on this reference work. Particularly, the surface tension term is discretized explicitly and therefore, a Stability Condition is induced on the computational time step. This constraint on the time step allows the containment of the amplification of capillary waves along the interface and puts more emphasis on the terms linked with the density in the Navier-Stokes equation (i. e. unsteady and inertia terms) rather than on the viscous terms. Indeed, the viscosity does not appear, as a parameter, in this Stability Condition. We propose a new Stability Condition which takes into account all fluid characteristics (density and viscosity) and for which we present a theoretical estimation. We detail the analysis which is based on a perturbation study - with capillary wave - for which we use energy estimate on the induced perturbed velocity. We validate our analysis and algorithms with numerical simulations of microfluidic flows using a Level Set method, namely the exploration of different mixing dynamics inside microdroplets.
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on Stability Condition for bifluid flows with surface tension application to microfluidics
Journal of Computational Physics, 2008Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:Models for incompressible immiscible bifluid flows with surface tension are here considered. Since Brackbill et al. [J.U. Brackbill, D.B. Kothe, C. Zemach, A continuum method for modeling surface tension, J. Comput. Phys. 100 (1992) 335-354] introduced the Continuum Surface Force (CSF) method, many methods involved in interface tracking or capturing are based on this reference work. Particularly, the surface tension term is discretized explicitly and therefore, a Stability Condition is induced on the computational time step. This constraint on the time step allows the containment of the amplification of capillary waves along the interface and puts more emphasis on the terms linked with the density in the Navier-Stokes equation (i.e. unsteady and inertia terms) rather than on the viscous terms. Indeed, the viscosity does not appear, as a parameter, in this Stability Condition. We propose a new Stability Condition which takes into account all fluid characteristics (density and viscosity) and for which we present a theoretical estimation. We detail the analysis which is based on a perturbation study - with capillary wave - for which we use energy estimate on the induced perturbed velocity. We validate our analysis and algorithms with numerical simulations of microfluidic flows using a Level Set method, namely the exploration of different mixing dynamics inside microdroplets.
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On Stability Condition for bifluid flows with surface tension: Application to microfluidics
Journal of Computational Physics, 2008Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:Accepted 22 February 2008 ; Available online 5 March 2008. Accepté pour publication le 22/08/2007 ; disponible en ligne le 05/04/2008 ; 41 pages.International audienceModels for incompressible immiscible bifluid flows with surface tension are here considered. Since Brackbill, Kothe and Zemach (J. Comput. Phys. 100, pp 335-354, 1992) introduced the Continuum Surface Force (CSF) method, many methods involved in interface tracking or capturing are based on this reference work. Particularly, the surface tension term is discretized explicitly and therefore, a Stability Condition is induced on the computational time step. This constraint on the time step allows the containment of the amplification of capillary waves along the interface and puts more emphasis on the terms linked with the density in the Navier-Stokes equation (i. e. unsteady and inertia terms) rather than on the viscous terms. Indeed, the viscosity does not appear, as a parameter, in this Stability Condition. We propose a new Stability Condition which takes into account all fluid characteristics (density and viscosity) and for which we present a theoretical estimation. We detail the analysis which is based on a perturbation study - with capillary wave - for which we use energy estimate on the induced perturbed velocity. We validate our analysis and algorithms with numerical simulations of microfluidic flows using a Level Set method, namely the exploration of different mixing dynamics inside microdroplets
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Level-Set method and Stability Condition for curvature-driven flows
Comptes rendus hebdomadaires des séances de l'Académie des sciences, 2007Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:We consider models for the simulation of curvature-driven incompressible bifluid flows, where the surface tension term is discretized explicitly. From this formulation a numerical Stability Condition arises for which we present a new theoretical estimation for low and medium Reynolds numbers. We illustrate our analysis with numerical simulations of microfluidic flows using Level Set method. Finally, we propose a method to reduce computational cost induced by this Stability Condition for low flow velocities.
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Level-Set method and Stability Condition for curvature-driven flows
Comptes Rendus Mathematique, 2007Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:International audienceWe consider models for the simulation of curvature-driven incompressible bifluid flows, where the surface tension term is discretized explicitly. From this formulation a numerical Stability Condition arises for which we present a new theoretical estimation for low and medium Reynolds numbers. We illustrate our analysis with numerical simulations of microfluidic flows using Level Set method. Finally, we propose a method to reduce computational cost induced by this Stability Condition for low flow velocities
Cédric Galusinski - One of the best experts on this subject based on the ideXlab platform.
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On Stability Condition for bifluid flows with surface tension : application to microfluidics
Journal of Computational Physics, 2008Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:Models for incompressible immiscible bifluid flows with surface tension are here considered. Since Brackbill, Kothe and Zemach (J. Comput. Phys. 100, pp 335-354, 1992) introduced the Continuum Surface Force (CSF) method, many methods involved in interface tracking or capturing are based on this reference work. Particularly, the surface tension term is discretized explicitly and therefore, a Stability Condition is induced on the computational time step. This constraint on the time step allows the containment of the amplification of capillary waves along the interface and puts more emphasis on the terms linked with the density in the Navier-Stokes equation (i. e. unsteady and inertia terms) rather than on the viscous terms. Indeed, the viscosity does not appear, as a parameter, in this Stability Condition. We propose a new Stability Condition which takes into account all fluid characteristics (density and viscosity) and for which we present a theoretical estimation. We detail the analysis which is based on a perturbation study - with capillary wave - for which we use energy estimate on the induced perturbed velocity. We validate our analysis and algorithms with numerical simulations of microfluidic flows using a Level Set method, namely the exploration of different mixing dynamics inside microdroplets.
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on Stability Condition for bifluid flows with surface tension application to microfluidics
Journal of Computational Physics, 2008Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:Models for incompressible immiscible bifluid flows with surface tension are here considered. Since Brackbill et al. [J.U. Brackbill, D.B. Kothe, C. Zemach, A continuum method for modeling surface tension, J. Comput. Phys. 100 (1992) 335-354] introduced the Continuum Surface Force (CSF) method, many methods involved in interface tracking or capturing are based on this reference work. Particularly, the surface tension term is discretized explicitly and therefore, a Stability Condition is induced on the computational time step. This constraint on the time step allows the containment of the amplification of capillary waves along the interface and puts more emphasis on the terms linked with the density in the Navier-Stokes equation (i.e. unsteady and inertia terms) rather than on the viscous terms. Indeed, the viscosity does not appear, as a parameter, in this Stability Condition. We propose a new Stability Condition which takes into account all fluid characteristics (density and viscosity) and for which we present a theoretical estimation. We detail the analysis which is based on a perturbation study - with capillary wave - for which we use energy estimate on the induced perturbed velocity. We validate our analysis and algorithms with numerical simulations of microfluidic flows using a Level Set method, namely the exploration of different mixing dynamics inside microdroplets.
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On Stability Condition for bifluid flows with surface tension: Application to microfluidics
Journal of Computational Physics, 2008Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:Accepted 22 February 2008 ; Available online 5 March 2008. Accepté pour publication le 22/08/2007 ; disponible en ligne le 05/04/2008 ; 41 pages.International audienceModels for incompressible immiscible bifluid flows with surface tension are here considered. Since Brackbill, Kothe and Zemach (J. Comput. Phys. 100, pp 335-354, 1992) introduced the Continuum Surface Force (CSF) method, many methods involved in interface tracking or capturing are based on this reference work. Particularly, the surface tension term is discretized explicitly and therefore, a Stability Condition is induced on the computational time step. This constraint on the time step allows the containment of the amplification of capillary waves along the interface and puts more emphasis on the terms linked with the density in the Navier-Stokes equation (i. e. unsteady and inertia terms) rather than on the viscous terms. Indeed, the viscosity does not appear, as a parameter, in this Stability Condition. We propose a new Stability Condition which takes into account all fluid characteristics (density and viscosity) and for which we present a theoretical estimation. We detail the analysis which is based on a perturbation study - with capillary wave - for which we use energy estimate on the induced perturbed velocity. We validate our analysis and algorithms with numerical simulations of microfluidic flows using a Level Set method, namely the exploration of different mixing dynamics inside microdroplets
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Level-Set method and Stability Condition for curvature-driven flows
Comptes rendus hebdomadaires des séances de l'Académie des sciences, 2007Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:We consider models for the simulation of curvature-driven incompressible bifluid flows, where the surface tension term is discretized explicitly. From this formulation a numerical Stability Condition arises for which we present a new theoretical estimation for low and medium Reynolds numbers. We illustrate our analysis with numerical simulations of microfluidic flows using Level Set method. Finally, we propose a method to reduce computational cost induced by this Stability Condition for low flow velocities.
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Level-Set method and Stability Condition for curvature-driven flows
Comptes Rendus Mathematique, 2007Co-Authors: Cédric Galusinski, Paul VigneauxAbstract:International audienceWe consider models for the simulation of curvature-driven incompressible bifluid flows, where the surface tension term is discretized explicitly. From this formulation a numerical Stability Condition arises for which we present a new theoretical estimation for low and medium Reynolds numbers. We illustrate our analysis with numerical simulations of microfluidic flows using Level Set method. Finally, we propose a method to reduce computational cost induced by this Stability Condition for low flow velocities
Wei Xing Zheng - One of the best experts on this subject based on the ideXlab platform.
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improved Stability Condition for takagi sugeno fuzzy systems with time varying delay
IEEE Transactions on Systems Man and Cybernetics, 2017Co-Authors: Zhiguang Feng, Wei Xing ZhengAbstract:In this paper, the Stability analysis problem of Takagi–Sugeno fuzzy systems with time-varying delay is investigated. By utilizing the Wirtinger-based integral inequality and the improved reciprocally convex combination technique, an improved Stability Condition is derived in terms of linear matrix inequalities. A numerical example is given to demonstrate the efficiency of the obtained result.
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Improved Stability Condition for Takagi–Sugeno Fuzzy Systems With Time-Varying Delay
IEEE transactions on cybernetics, 2016Co-Authors: Zhiguang Feng, Wei Xing ZhengAbstract:In this paper, the Stability analysis problem of Takagi-Sugeno fuzzy systems with time-varying delay is investigated. By utilizing the Wirtinger-based integral inequality and the improved reciprocally convex combination technique, an improved Stability Condition is derived in terms of linear matrix inequalities. A numerical example is given to demonstrate the efficiency of the obtained result.
Limin Wang - One of the best experts on this subject based on the ideXlab platform.
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A Stability Condition for turbulence model: From EMMS model to EMMS-based turbulence model
Particuology, 2014Co-Authors: Lin Zhang, Xiaoping Qiu, Limin WangAbstract:Abstract The closure problem of turbulence is still a challenging issue in turbulence modeling. In this work, a Stability Condition is used to close turbulence. Specifically, we regard single-phase flow as a mixture of turbulent and non-turbulent fluids, separating the structure of turbulence. Subsequently, according to the picture of the turbulent eddy cascade, the energy contained in turbulent flow is decomposed into different parts and then quantified. A turbulence Stability Condition, similar to the principle of the energy-minimization multi-scale (EMMS) model for gas–solid systems, is formulated to close the dynamic constraint equations of turbulence, allowing the inhomogeneous structural parameters of turbulence to be optimized. We name this model as the “EMMS-based turbulence model”, and use it to construct the corresponding turbulent viscosity coefficient. To validate the EMMS-based turbulence model, it is used to simulate two classical benchmark problems, lid-driven cavity flow and turbulent flow with forced convection in an empty room. The numerical results show that the EMMS-based turbulence model improves the accuracy of turbulence modeling due to it considers the principle of compromise in competition between viscosity and inertia.
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A Stability Condition for turbulence model: From EMMS model to EMMS-based turbulence model
Particuology, 2014Co-Authors: Lin Zhang, Xiaoping Qiu, Limin WangAbstract:The closure problem of turbulence is still a challenging issue in turbulence modeling. In this work, a Stability Condition is used to close turbulence. Specifically, we regard single-phase flow as a mixture of turbulent and non-turbulent fluids, separating the structure of turbulence. Subsequently, according to the picture of the turbulent eddy cascade, the energy contained in turbulent flow is decomposed into different parts and then quantified. A turbulence Stability Condition, similar to the principle of the energy-minimization multi-scale (EMMS) model for gas-solid systems, is formulated to close the dynamic constraint equations of turbulence, allowing the heterogeneous structural parameters of turbulence to be optimized. We call this model the `EMMS-based turbulence model', and use it to construct the corresponding turbulent viscosity coefficient. To validate the EMMS-based turbulence model, it is used to simulate two classical benchmark problems, lid-driven cavity flow and turbulent flow with forced convection in an empty room. The numerical results show that the EMMS-based turbulence model improves the accuracy of turbulence modeling due to it considers the principle of compromise in competition between viscosity and inertia.Comment: 26 pages, 13 figures, 2 table
Zhiguang Feng - One of the best experts on this subject based on the ideXlab platform.
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improved Stability Condition for takagi sugeno fuzzy systems with time varying delay
IEEE Transactions on Systems Man and Cybernetics, 2017Co-Authors: Zhiguang Feng, Wei Xing ZhengAbstract:In this paper, the Stability analysis problem of Takagi–Sugeno fuzzy systems with time-varying delay is investigated. By utilizing the Wirtinger-based integral inequality and the improved reciprocally convex combination technique, an improved Stability Condition is derived in terms of linear matrix inequalities. A numerical example is given to demonstrate the efficiency of the obtained result.
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Improved Stability Condition for Takagi–Sugeno Fuzzy Systems With Time-Varying Delay
IEEE transactions on cybernetics, 2016Co-Authors: Zhiguang Feng, Wei Xing ZhengAbstract:In this paper, the Stability analysis problem of Takagi-Sugeno fuzzy systems with time-varying delay is investigated. By utilizing the Wirtinger-based integral inequality and the improved reciprocally convex combination technique, an improved Stability Condition is derived in terms of linear matrix inequalities. A numerical example is given to demonstrate the efficiency of the obtained result.
