Fidelity Pointwise Grid Cell Remediation Method for Overset Meshes
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Elliptic Grid Equations
The construction of an individual structured mesh is usually treated as either a partial or full boundary value problem (BVP).
For partial BVPs, a 3D mesh is "extruded" from a surface mesh, generally by algebraic or PDE-based techniques. For full
BVPs, the six sides of a computational block are first constructed and then serve as the boundaries for methods that place
interior nodes at locations that attempt to maintain a degree of smoothness, user-expected clustering, and cell orthogonality.
Base and Adaptive Control Functions
Control functions are used to influence the positioning of grid point locations on the interior of the mesh. The intent is to
reduce orphan cells and poor foreign cell to local cell disparities, thereby increasing the quality of the mesh-mesh interpo-
lation, and also improving the quality of the CFD solution.
Figure 4. Adaption to ΔS field
Parametric Form of Elliptic Equations
A third solution, and the one employed herein, is to solve the elliptic grid equations recast in parametric form so that the
equations are defined in terms of the computational coordinates of the original grid.
Use in Overset Grids
The remaining task in using the elliptic grid equations to remediate disparities between a volume grid's cells and foreign cell
sizes is to form the weighting vector field at each point in the mesh. The overset grid assembly data is used to define a target
length scale that is a tensor of grid spacing in the local grid's component directions.
