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## Full-Text Articles in Engineering

Unstructured Grid Algorithms For Two- And Three-Dimensional Flows On Parallel Computers , Thomas Hans Ramin

#### Unstructured Grid Algorithms For Two- And Three-Dimensional Flows On Parallel Computers , Thomas Hans Ramin

*Retrospective Theses and Dissertations*

The Navier-Stokes equations are solved numerically for two-and three-dimensional viscous laminar flows. The domain is discretized using triangular control volumes in two dimensions and tetrahedra in three dimensions, using existing grid generators. The flow solvers are implemented on a variety of computers, including distributed memory parallel computers;A finite-volume approach is used to discretize the governing flow equations in conservation law form using conserved variables. A cell centered approach is used where the unknowns are computed at the center of each control volume. Both explicit and implicit solution strategies are pursued. In the two-dimensional version of the algorithm an explicit ...

Unstructured Surface And Volume Decimation Of Tessellated Domains , Kevin Joseph Renze

#### Unstructured Surface And Volume Decimation Of Tessellated Domains , Kevin Joseph Renze

*Retrospective Theses and Dissertations*

A general algorithm for decimating unstructured discretized data sets is presented. The discretized space may be a planar triangulation, a general 3D surface triangulation, or a 3D tetrahedrization. The decimation algorithm enforces Dirichlet boundary conditions, uses only existing vertices, and assumes manifold geometry. Local dynamic vertex removal is performed without history information while preserving the initial topology and boundary geometry. The tessellation at each step of the algorithm is preserved and, in the pathological case, every interior vertex is a candidate for removal. The research focuses on how to remove a vertex from an existing unstructured n-dimensional tessellation, not on ...

A Compliant Model For Estimation And Optimization Of Damping In Vibrating Structures , Thomas Jeffrey Thompson

#### A Compliant Model For Estimation And Optimization Of Damping In Vibrating Structures , Thomas Jeffrey Thompson

*Retrospective Theses and Dissertations*

Proposed future space missions involve large structures which must maintain precise dimensional tolerances even during dynamic maneuvers. In order to attenuate disturbances in the many modes of vibration of such a structure, active and passive vibration control are proposed. The passive control is to be achieved by placing viscous or viscoelastic members or materials within a structure in order to absorb energy. Ascertaining the best combination of locations for such treatments is difficult due to the large number of cases, each of which requires computationally expensive complex eigenvalue analyses of a finite element model to compute modal damping values;In ...