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Showing 1 to 20 of 22 for “"Variational Multiscale"”.
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A variational multiscale framework for non-Newtonian fluid models
… implementations. In this dissertation, the Variational Multiscale (VMS) framework is employed to derive stabilized mixed formulations for advection-diffusion, shear-rate dependent, viscoelastic, and shear-rate dependent viscoelastic fluid models. The VMS framework leads to a two-level …
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A variational multiscale computational framework for nonlinear interfacial solid mechanics
… approach for deriving these components is the Variational Multiscale (VMS) method, a guiding philosophy for recovering stability through the modeling of features that are filtered out by discretization. The enhanced stability of the framework enables the treatment of various interface …
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Data-Driven Variational Multiscale Reduced Order Modeling of Turbulent Flows
… centers around the hierarchical structure of the variational multiscale (VMS) methodology and utilizes data to increase the ROM accuracy at a modest computational cost. The VMS methodology is a natural fit for the hierarchical structure of the ROM basis: In the first step, we use the ROM …
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An adaptive variational multiscale method with discontinuous subscales for aerodynamic flows
… consistent and stable. The scheme, called Variational Multiscale with Discontinuous subscales (VMSD), models unresolved solution perturbations with a discontinuous representation. The solution discontinuities are then used to stabilize the problem using methods borrowed from discontinuous …
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A variational multiscale a-posteriori error estimation method for nearly incompressible elasticity
… incompressible elasticity that is based on variational multiscale concepts. The displacement field is decomposed into coarse scales captured by the finite element mesh and fine scales representing the part of the physics unresolved by the mesh. This solution field decomposition addresses the …
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Variational multiscale method for coupled systems: free-surface flows and stratified turbulence
… scalar PDE. The method is derived based on the variational multiscale (VMS) framework. Specifically, two classes of coupled systems are considered: free-surface flows with a sharp interface marker and stratified turbulence with a smooth temperature field. The additional nonlinearity introduced …
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Variational multiscale method for fluid-structure interaction on non-matching meshes and turbulent flows around immersed objects
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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A locally conservative variational multiscale method for the simulation of porous media flow with multiscale source terms
Multiscale phenomena are ubiquitous to flow and transport in porous media. They manifest themselves through at least the following three facets: (1) effective parameters in the governing equations are scale dependent; (2) some features of the flow (especially sharp fronts and boundary layers) …
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A variational multiscale computational framework for reaction-dominated thermo-chemo-mechanical process modeling in multi-constituent material systems
… two major components of the work: (i) new robust variational multi-scale numerical methods that are consistently derived, and (ii) models for multi-physics processes in multi-constituent materials. New robust numerical methods are developed via the variational multiscale (VMS) framework. Through …
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Reduced-Order Modeling of Complex Engineering and Geophysical Flows: Analysis and Computations
… flows: the dynamic subgrid-scale model and the variational multiscale model. These models, which are considered state-of-the-art in large eddy simulation, are carefully derived and numerically investigated. Since modern closure models for turbulent flows generally have non-polynomial …
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Stabilized Finite Element Formulations for Flow Problems
… of the work is a consistent linearization of a variational multiscale formulation for incompressible Navier-Stokes. We compare the convergence of this formulation with a fixed-point iteration technique. We show for a number of example problems that the Newton-Raphson technique converges …
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Numerical Analysis for Data-Driven Reduced Order Model Closures
… Thus, we propose a new ROM, the data-driven variational multiscale ROM (DD-VMS-ROM) built by adding a closure term to the G-ROM, aiming to increase the numerical accuracy of the ROM approximation without decreasing the computational efficiency. The closure term is constructed based on the …
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Patient-Specific Computer Modeling of Blood Flow in Cerebral Arteries With Aneurysm and Stent
… which is the space–time version of the variational multiscale (VMS) method and is called “DST/SST-VMST.” The special techniques include using NURBS for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and …
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Flow Analysis of Vibration Modes in Turbocharger Turbines
… The core computational method is the Space–Time Variational Multiscale (ST-VMS) method. The ST-VMS serves as a moving mesh method. That enables mesh-resolution control near the rotor surfaces and high-resolution boundary-layer representation. The core method is complemented with the “ST-SI-IGA,” …
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On the Application of an Output-based Adaptive, Higher-order Finite Element Method to Sonic Boom Propagation
… finite element method. The research employs the Variational Multiscale with Discontinuous Subscales (VMSD) method, integrating Continuous Galerkin (CG) and Discontinuous Galerkin (DG) features, referred to as VMSD-BR2. This approach leverages static condensation to manage computational cost while …
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Residual-based turbulence models for incompressible flows in domains with moving boundaries
… interfaces. The method is derived employing the Variational Multiscale (VMS) framework, which gives rise to several modeling options that are exploited to obtain accurate turbulence models. To accommodate problems with moving boundaries such as fluid-structure interaction and free-surface …
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A variational framework for multi-scale defect modeling in strained electronics and processing of composite materials
… defect modeling framework based on a system of variationally consistent formulations that allow for the modeling of the material processing stage and incorporate multi-physics coupling for multi-constituent materials. A stabilized and novel discontinuity capturing formulation is developed to …
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A unified computational framework for process modeling and performance modeling of multi-constituent materials
This Dissertation was approved for publication on 2016-09-06 at 08:58.
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Advancing Maternal Health through Projection-based and Machine Learning Strategies for Reduced Order Modeling
… In our first study, a new data-driven (DD) variational multiscale (VMS) ROM framework was extended to obtain the displacement fields of rat vaginal tissue subjected to ramping luminal pressure. For comparison purposes, we also investigated the classical Galerkin ROM (G-ROM). In our numerical …
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Computational methods for coupled multiphysics transport problems
This Dissertation was approved for publication on 2024-08-06 at 12:11.
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