Automated moving mesh techniques in CFD. Application to fluid-structure interactions and rigid motions problems

In the Computational Fluid Dynamics (CFD) simulation codes, the physical domain is divided into a finite number of small control volumes, corresponding to the cells of a computational grid, where discrete versions of the integral form of the continuum transport equations are applied. For the simulation of the moving meshes (fluids or solids), we employ specific morphing techniques combined with rigid motions. Since morphing strategies can easily lead to poor quality cells, it becomes important to keep under control the topological deformations that can take place both into the surface mesh and into the volume cells, by means of specific mesh quality metrics and re-meshing procedures. The work done in getting the control of the morphing/re-meshing techniques in order to use them in applications that principally treat with fluid-structure interactions and rigid bodies motions is here presented. In such applications, when local deformations of surfaces occur, bad topological effects like warped, twisted or self-intersected faces can easily lead to the appearance of negative volume cells, determining the simulation to stop running. We give a demonstration of how various morphing techniques have been applied to simulations that especially treat with structural and moving parts, in particular, in cases where the deformations arise from considerations related to solid displacements and stresses (pipe's walls vibrations) or to rigid body motions (translations). Surface boundary mesh extraction and CAD geometry updating strategies to avoid mesh degeneration are investigated and developed. Java programming is employed for the automation of the re-meshing procedures.

@InProceedings{Pro12b,
  author       = {Profir, M.},
  title        = {Automated moving mesh techniques in CFD. Application to fluid-structure interactions and rigid  motions problems},
  booktitle    = {Collana seminari interni 2012},
  number       = {20120411},
  month        = {april},
  year         = {2012},
  keywords     = {moving meshes, morphing, re-meshing, deformation, automation},
  url          = {https://publications.crs4.it/pubdocs/2012/Pro12b},
}