Global ETD Search
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 54 for “"time marching"”.
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A time marching boundary element method for the prediction of the flow around surface piercing hydrofoils
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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Aeroelasticity of Morphing Wings Using Neural Networks
… and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the …
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A space-time adaptive method for flows in oil reservoirs
This work presents a space-time adaptive framework for simulating multi-phase flows through porous media, with specific applications to flows in oil reservoirs. A fully unstructured discretization of space and time is used instead of a conventional time-marching approach. For d-dimensional spatial …
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Development of a new shock capturing formula for pressure correction methods
… pressure correction procedure and Denton's time marching procedure. The time marching procedure is traditionally used for transonic flow calculations, whereas the pressure correction method is better suited for incompressible and subsonic flows. However, the focus of this research is on the …
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Análise dinâmica elasto-plástica de transiente de curta duração incluindo os efeitos da interação solo-fluido-estrutura
… non-linearity. The central difference explicit time marching schem is adopted for integration of the dynamic equilibrium equation and a diagonal lumped mass matrix is employed with a special procedure applicable to variable nodal points quadrilateral isoparametric elements. The effects of …
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A time-spectral hybridizable discontinuous Galerkin method for periodic flow problems
Numerical simulations of time-periodic flows are an essential design tool for a wide range of engineered systems, including jet engines, wind turbines and flapping wings. Conventional solvers for time-periodic flows are limited in accuracy and efficiency by the low-order Finite Volume and …
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Matrix-free time-domain methods for general electromagnetic analysis
… methods, the explicit finite-difference time-domain (FDTD) method is free of matrix solutions. However, it requires a structured orthogonal grid for space discretization. In this work, we develop a new time-domain method that naturally requires no matrix solution, regardless of whether …
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Um esquema eficiente para a análise dinâmica transiente com o método dos elementos de contorno
This work concerns the optimization of the time marching scheme commonly used to obtain numerical Boundary Element Method solutions for two-dimensional transient problems governed by the Scalar Wave Equation. Two truncating schemes are proposed, named Intermediate and Mixed, which permit control …
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The unstructured grid incompressible Navier-Stokes algorithm for convective heat transfer based on artificial compressibility
… is used to solve the resulting equations in a time marching fashion. Roe's approximate Riemann solver is used for the construction of the numerical flux. An eigensystem is derived for the flux Jacobian matrix, which is used in the evaluation of the numerical flux and the characteristic variable …
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A DG HWENO scheme for hyperbolic equations
… approach for building a limiter for Runge-Kutta time marching schemes which reconstructs the higher order moments of troubled cells using only information of neighboring cells. This technique is used to develop a limiter in 1-D for P₂ to P₅ interpolants on non-uniform grids and in 2-D for P₂ …
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An adaptive space-time discontinuous Galerkin method for reservoir flows
… a fully-automated manner. In particular, a space-time discontinuous Galerkin (DG) finite element method is used to achieve a high-order discretization on a fully unstructured space-time mesh, instead of a conventional time-marching approach. Anisotropic mesh adaptation is performed to reduce the …
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A Continuous/Discontinuous FE Method for the 3D Incompressible Flow Equations
… order derivatives. In order to enable large time steps for time marching to steady-state and time evolving problems, implicit scheme is used in connection with high order implicit RK methods. Numerical tests demonstrate that the overall scheme is accurate and computationally efficient.</p>
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Numerical investigation of time-integration schemes applicable to fluid-structure interaction
… to be recast in state-space form. The implicit time-marching schemes studied in this thesis are limited to the Backward Differentiation Formula (BDF) schemes, Modified Extended-BDF schemes, and a Singly-Diagonal Implicit Runge-Kutta (SDIRK) method. Verification and validation of temporal and …
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A 3-dimensional H-adaptive algorithm for groundwater flow and contaminant transport
… Darcy's law for an anisotropic medium, and the time-dependent species transport equations. Petrov-Galerkin weighting of the advection terms provides numerical stability. An explicit time marching scheme is used to solve the transient equations. By utilizing unstructured adaptive meshing, …
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Numerical simulation of acoustic waves in a rectangular chamber
… cycles. A stack of heat exchanger plates are sometimes included. The study is motivated by thermoacoustic refrigeration, a phenomena which uses soundwaves in a chamber to achieve a cooling effect.</p><p>The present study treats the flow numerically. The governing equations are the viscous …
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Método dos elementos de contorno aplicado a propagação de ondas gravitacionais não lineares
… to update the boudary fluid particles at each time step. An Eulerian formulation is employed to solve the boundary value problem at each time step. Velocity potencial and normal velocities at boundary nodes, at each time are obtained by the boundary element method. The time marching process is …
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Investigation of a space-time adaptive method for bluff body flows
… This thesis investigates an unstructured spacetime adaptive framework for unsteady ow simulations of the compressible Navier-Stokes equations. A fully-unstructured discretization of space and time is used: for d-dimensional spatial problems, (d + 1)-dimensional meshes are generated, where time …
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Methodologies for Broadband Electromagnetic Modeling of on-Chip Semiconductor Substrate Noise
… elaborates on a number of features for the time domain finite integration technique (FIT), a volumetric discretization scheme, aimed at improving its computational performance for the type of geometrical characteristics encountered in substrate coupling problems on-chip. Along these lines, …
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Time domain modeling of unsteady aerodynamic forces on a flapping airfoil
… and pitching types of motion and develop a time marching simulation based on early work in unsteady aerodynamics. The ability of the code to compute lift and thrust forces is validated against published results. We then study ways to maximize thrust generation by considering sinusoidal and …
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A Lumped Computational Model for Sodium Sulfur Battery Analysis
Due to the cost of materials and time consuming testing procedures, development of new batteries is a slow and expensive practice. The purpose of this study is to develop a computational model and assess the capabilities of such a model designed to aid in the design process and control of sodium …
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