10,659 research outputs found
Geometry Modeling for Unstructured Mesh Adaptation
The quantification and control of discretization error is critical to obtaining reliable simulation results. Adaptive mesh techniques have the potential to automate discretization error control, but have made limited impact on production analysis workflow. Recent progress has matured a number of independent implementations of flow solvers, error estimation methods, and anisotropic mesh adaptation mechanics. However, the poor integration of initial mesh generation and adaptive mesh mechanics to typical sources of geometry has hindered adoption of adaptive mesh techniques, where these geometries are often created in Mechanical Computer- Aided Design (MCAD) systems. The difficulty of this coupling is compounded by two factors: the inherent complexity of the model (e.g., large range of scales, bodies in proximity, details not required for analysis) and unintended geometry construction artifacts (e.g., translation, uneven parameterization, degeneracy, self-intersection, sliver faces, gaps, large tolerances be- tween topological elements, local high curvature to enforce continuity). Manual preparation of geometry is commonly employed to enable fixed-grid and adaptive-grid workflows by reducing the severity and negative impacts of these construction artifacts, but manual process interaction inhibits workflow automation. Techniques to permit the use of complex geometry models and reduce the impact of geometry construction artifacts on unstructured grid workflows are models from the AIAA Sonic Boom and High Lift Prediction are shown to demonstrate the utility of the current approach
Unstructured mesh algorithms for aerodynamic calculations
The use of unstructured mesh techniques for solving complex aerodynamic flows is discussed. The principle advantages of unstructured mesh strategies, as they relate to complex geometries, adaptive meshing capabilities, and parallel processing are emphasized. The various aspects required for the efficient and accurate solution of aerodynamic flows are addressed. These include mesh generation, mesh adaptivity, solution algorithms, convergence acceleration, and turbulence modeling. Computations of viscous turbulent two-dimensional flows and inviscid three-dimensional flows about complex configurations are demonstrated. Remaining obstacles and directions for future research are also outlined
Unstructured mesh algorithms for aerodynamic calculations
The use of unstructured mesh techniques for solving complex aerodynamic flows is discussed. The principle advantages of unstructured mesh strategies, as they relate to complex geometries, adaptive meshing capabilities, and parallel processing are emphasized. The various aspects required for the efficient and accurate solution of aerodynamic flows are addressed. These include mesh generation, mesh adaptivity, solution algorithms, convergence acceleration, and turbulence modeling. Computations of viscous turbulent two-dimensional flows and inviscid three-dimensional flows about complex configurations are demonstrated. Remaining obstacles and directions for future research are also outlined
Local bisection for conformal refinement of unstructured 4D simplicial meshes
We present a conformal bisection procedure for
local refinement of 4D unstructured simplicial meshes with
bounded minimum shape quality. Specifically, we propose a
recursive refine-to-conformity procedure in two stages, based on
marking bisection edges on different priority levels and defining
specific refinement templates. Two successive applications
of the first stage ensure that any 4D unstructured mesh can
be conformingly refined. In the second stage, the successive
refinements lead to a cycle in the number of generated similarity
classes and thus, we can ensure a bound over the minimum
shape quality. In the examples, we check that after successive
refinement the mesh quality does not degenerate. Moreover, we
refine a 4D unstructured mesh and a space-time mesh (3D + 1D)
representation of a moving object
A local, un-structured, re-meshing technique capable of handling large body-motion in rotating machinery
In this paper we propose a simple, unstructured mesh generation technique that is capable of handling the large and complex blade motion that is encountered in certain rotating machines, such as vertical axis wind turbines or cycloidal propellers. The technique is characterised by localised re-meshing and interpolation, so as to keep the mesh generation cost and interpolation error as low as possible
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