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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 53 for “"Order of Accuracy"”.
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Improved dynamic structural analysis for linear and nonlinear systems
A new family of higher-order implicit, one-step integration algorithms has been developed and evaluated with respect to stability, accuracy, convergence, dissipation, dispersion and overshoot behavior. These algorithms have minimum order of accuracy two, and maximum order of accuracy four. In …
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Waveform methods for ordinary differential equations
… an iterative technique for solving systems of differential equations, can be used to reduce the processing time. Waveform method has been shown to converge superlinearly on finite intervals. In this thesis, a measure of speed of convergence is defined and is used to compare the value of …
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A correction function method to solve incompressible fluid flows to high accuracy with immersed geometries
Numerical simulations of incompressible viscous flows in realistic configurations are increasingly important in many scientific and engineering fields. In Aeronautics, for instance, relatively cheap numerical computations replace costly hours of wind tunnel investigations in the early design stages …
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Code Verification and Numerical Accuracy Assessment for Finite Volume CFD Codes
A detailed code verification study of an unstructured finite volume Computational Fluid Dynamics (CFD) code is performed. The Method of Manufactured Solutions is used to generate exact solutions for the Euler and Navier-Stokes equations to verify the correctness of the code through order of …
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A Hermite Cubic Immersed Finite Element Space for Beam Design Problems
… is based upon meshes that can be independent of interface of the materials used to form a beam. Both the forward and inverse problems associated with the beam equation are considered. The order of accuracy of this IFE space is numerically investigated from the point of view of both the …
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Semi-implicit schemes for compressible fluids in elastic pipes and a-posteriori sub-cell finite volume limiting techniques for semi-implicit Discontinuous Galerkin schemes for hyperbolic conservation laws on staggered meshes
In the present work we solve systems of partial differential equations (PDE) for hyperbolic conservation laws using semi-implicit numerical methods on staggered meshes applied both to the class of finite volume (FV) and both to the family of high order Discontinuous Galerkin (DG) finite elements …
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Numerical Simulation of the Fluid-Structure Interaction of a Surface Effect Ship Bow Seal
Numerical simulations of fluid-structure interaction (FSI) problems were performed in an effort to verify and validate a commercially available FSI tool. This tool uses an iterative partitioned coupling scheme between CD-adapco's STAR-CCM+ finite volume fluid solver and Simulia's Abaqus finite …
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The development of an all quadrilateral boundary conforming grid generator for high order finite element methods
… scheme is automated to work for arbitrary choice of geometry. In addition, a Non-Uniform Rational B-Spline curve fitter is implemented to replicate the curvature of the geometries. The grid elements on the boundaries conform to the curved structure to support high order accuracy for a finite …
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Forward modeling the gravitational field using a direct solution of Poisson's equation
Forward modeling of gravity data typically computes the vertical gravitational acceleration using either closed-form formulae, or numerical solution of Poisson's equation governing the gravity potential followed by numerical differentiation. We present a method for computing the vertical gravity …
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Analysis and Implementation of High-Order Compact Finite Difference Schemes
The derivation of centered compact schemes at interior and boundary grid points is performed and an analysis of stability and computational efficiency is given. Compact schemes are high order implicit methods for numerical solutions of initial and/or boundary value problems modeled by differential …
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Numerical investigation of time-integration schemes applicable to fluid-structure interaction
… for analysis and proper design. The simulation of this phenomenon requires the application of high-fidelity numerical methods. In the current work, the fluid and structural equations both utilize the same multistep or multistage schemes for temporal advancement. This requires the structural …
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Error analysis of higher order time-domain finite element methods for the one-dimensional Maxwell's equations
… element method has been extended for higher order temporal accuracy using several schemes. While common in computational fluid dynamics, less research has been conducted with these methods for computational electromagnetics. A stabilized finite element method utilizing the Streamline/Upwind …
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CINAPACT-Splines: A Family of Infnite Smooth, Accurate and Compactly Supported Splines
We introduce a class of compactly supported C infinite kernels (CINAPACT-splines) whose integer translates form a shift-invariant reconstruction space that can be tuned to achieve any order of accuracy. CINAPACT-splines resemble traditional B-splines in that higher orders of accuracy are achieved …
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Rapid Approximation of Bilinear Forms Involving Matrix Functions Through Asymptotic Analysis of Gaussian Node Placement
… stiffness has been introduced into systems of ordinary differential equations (ODEs) that arise from spatial discreti zation of partial differential equations (PDEs). The components of the solutions to these systems are coupled and changing at widely varying rates, which present problems for …
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Interplay of Electrical, Mechanical and Thermal Fields in III-N Nanostructures for LED Applications
This work aims at exploring the competing effects of various internal/built-in fields on the electronic structure and optical properties of III-N nanostructured (Quantum Dots and disk-in-a-wire) LEDs using a multiscale modeling approach. The objective is three-fold: (1) calculate the strain …
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Multigrid solution for high-order discontinuous Galerkin discretizations of the compressible Navier-Stokes equations
A high-order discontinuous Galerkin finite element discretization and p-multigrid solution procedure for the compressible Navier-Stokes equations are presented. The discretization has an element-compact stencil such that only elements sharing a face are coupled, regardless of the solution space. …
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Stabilized finite elements for compressible turbulent Navier-Stokes
… element approach is utilized in the development of a high-order flow solver for compressible turbulent flows. The Reynolds averaged Navier-Stokes (RANS) equations and modified Spalart-Almaras (SA) turbulence model are discretized using the streamline/upwind Petrov-Galerkin (SUPG) scheme. A fully …
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Structural analysis and optimization with a locally-Cartesian Hybrid Shell Model
… model well suited for conceptual design of aerospace vehicles. Although significantly simpler and more economical than full 3D elasticity models, it can still capture full 3D geometries, large deformations, and anisotropic materials. HSM is formulated from the full 3D equilibrium and …
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Verification of Compressible and Incompressible Computational Fluid Dynamics Codes and Residual-based Mesh Adaptation
Code verification is the process of ensuring, to the degree possible, that there are no algorithm deficiencies and coding mistakes (bugs) in a scientific computing simulation. In this work, techniques are presented for performing code verification of boundary conditions commonly used in …
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The construction of an ellipsometer to measure the refractive index and thickness of thin films.
… optical instruments, is a delicate piece of equipment requiring care in its construction, maintenance and operation. Since multiple reflections and birefringence in the optical components introduce large instrumental errors, a correct choice of component parts must be made so as to …
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