Research On And Implementation Of An Interactive Geometry User Environment And Some Key Technologies Of The High End Digital Prototyping

HEDP (High End Digital Prototyping) is a CAE software which developed by the CESC (Center for Engineering and Scientific Computation) , Zhejiang University. It is composed of pre-processing modules, post-processing modules, numerical computing modules and other modules to supporting numerical simulation services, such as parallel computing control module, remote task submission module, etc. It provides an integrated software platform and many enabling technology tools for the numerical solution of physical fields based on PDEs (Partial Differential Equations), such as the problems of CFD (Computational Fluid Dynamics), CSD (Computational Solid Dynamics) and etc. At present, HEDP has been gradually applied to the numerical simulations and verifications of scientific and engineering problems in aeronautic and astronautic fields.'Geometry Builder' is the pre-processing user interface in HEDP, under which IGUE (Interactive Geometry and User Environment) provides all geometric functionalities. This dissertation firstly illuminates the design and implementation of IGUE. Built on a B-Rep for solid modeling, IGUE provides a series of construction, edition, and visualization tools for geometric and topologic objects. Besides, IGUE contains abundant functionalities oriented to unstructured mesh generation, such as creation and visualization of background meshes and grid sources. Moreover, IGUE makes it rather easy to translate a geometry object from commercial CAD software to HEDP with the help of a translator based on the read or write operations of neutral files. Some CAD data validity verification and repair tools are also provide to idealize the dirty geometry objects, and make the subsequent surface meshing process a success.Mainstream mesh generation techniques are valid only for single domains, where manifold geometry rules are met. However, many problems require a mesh for non-manifold geometries, where a multi-domain mesh generation is required to integrate the single-domain methods to fulfill the multi-domain problems. This dissertation designs a bottom-up algorithmic framework for multi-domain mesh generation, where points are discretized before curves, and curves are discretized before surfaces, and so on. Shared entities (points/curves/surfaces) are guaranteed to be discretized only once, and no overlapping happens. Additionally, element reordering algorithms for surface or volume boundaries are afforded to orient the boundary elements.Eventually, this dissertation takes CGNS as the medium, completing the integration of HEDP and PCP, a parallel simulation software for Scramjet. Numerical experiments are presented to demonstrate the validity of the integration strategy.