Issue link: https://resources.system-analysis.cadence.com/i/1472753
Fidelity Pointwise Grid Cell Remediation Method for Overset Meshes Cadence is a pivotal leader in electronic design and computational expertise, using its Intelligent System Design strategy to turn design concepts into reality. Cadence customers are the world's most creative and innovative companies, delivering extraordinary electronic products from chips to boards to systems for the most dynamic market applications. www.cadence.com © 2022 Cadence Design Systems, Inc. All rights reserved worldwide. Cadence, the Cadence logo, and the other Cadence marks found at www.cadence.com/go/trademarks are trademarks or registered trademarks of Cadence Design Systems, Inc. All other trademarks are the property of their respective owners. 07/22 DB/JC/RS/WP-GRD-CLL/PDF Grid Cell Remediation in Unstructured Meshes Unstructured meshes are those that require explicit connectivity data specifying how cells link to one another. Although unstructured meshes have been used with great success in CFD for several decades, their usage in overset grids is relatively recent. This is because the rapidly developing moving grid technology is wholly dependent on overset grids, where it is impractical to generate new meshes for every time step, even while automating mesh algorithms that some unstructured techniques offer. Figure 5. Cross-section of unstructured background grid and near-body prismatic grid colored by cell volume before grid refinement (left) and after grid refinement (right) Remediation of unstructured isotropic tetrahedral meshes is considerably less involved than its structured counterpart, simply because the regions of the cell size disparity between the local and foreign cells are treatable via the insertion of grid points in the local mesh. Refinement of an unstructured isotropic tetrahedral mesh is accomplished by passing the current grid and a target edge length at each point in the grid to the tetrahedral mesher. Conclusion The results for the automated remediation of disparities in cell sizes in the vicinity of overlap regions in overset meshes validate their ability to improve both structured and unstructured mesh disparity with overlapping foreign grids. There are three additional areas of research that need further study. First, a more formal assessment of the ability of these methods to reduce interpolation errors (manifest as orphan points) in an automated sense. Next, the determination of the anisotropic target length scale for unstructured remediation needs further development. Finally, the structured grid redistribution algorithm is currently coded to move points interior to the boundaries only. Reference 1. Steinbrenner, John P., and Wyman, Nick J., "Automatic Structured and Unstructured Grid Cell Remediation for Overset Meshes," AIAA paper no. 2014-0779, January 2014: https://arc.aiaa.org/doi/10.2514/6.2014-0779