A generalized meshing environment for adaptive computational fluid dynamics.

摘要

The objective of this dissertation is to develop, implement, and apply new and advanced methodologies for a variety of meshing operations for adaptive computational fluid dynamics. A transfinite blending function interpolation method was developed to generate multi-block structured hexahedral meshes from CAD data files of a geometry and a new advancing front method was developed to generate unstructured tetrahedral meshes. Meshes were generated, using the new methods, for complete missiles, aircraft, and propulsion system components. Mesh smoothing methods were developed for both structured and unstructured meshes. Existing meshes from other codes can be repaired, smoothed and generally improved. Any existing mesh can be locally remeshed, h-refined, or the element type changed.; A set of new and reliable adaptive meshing algorithms was developed which uses an existing mesh file and a corresponding CFD solution file. The existing mesh is adaptively changed using the CFD solution and an element-by-element error-indicator criteria. The solution is then interpolated (conservatively) and re-written onto the new mesh. An existing CFD solver was modified to use the new meshing methodologies. This solver utilizes an unstructured mesh technique for both viscous incompressible and inviscid compressible flows in arbitrary geometries.; This dissertation presents the theoretical basis for the meshing methodologies and the CFD solution methodologies and describes the computer software package. Validation cases are then presented and compared to experimental data with excellent results. The suite of CFD cases computed in this project consist of (1) steady flows with adaptive refinement consisting of natural convection in a cavity, transonic and supersonic flow over a classic airfoil and inviscid flow over a complete aircraft configuration; (2) unsteady incompressible viscous flow with adaptive moving meshes consisting of a two-phase solidification front movement and a crystal growth process in a furnace; and (3) three-dimensional unsteady compressible flow with moving boundaries consisting of a defensive missile seeker-window shroud removal simulation and a stage separation event at supersonic speed. The results of the dissertation project are a new and reliable set of adaptive meshing algorithms, methodology, and computer software to advance the state-of-the-art in solution-adaptive modeling for computational fluid dynamics.