Zakharov A.   Димитриенко Ю.И.  

Development of Preprocessor of SIGMA Software Package for Generating Adaptive Grids

Reporter: Zakharov A.

Software package SIGMA is used for numerical solution of a wide range of problems in continuum mechanics. It includes a full set of modules that are required for the numerical simulation. SIGMA preprocessor includes a three-dimensional geometric simulation module, which allows to generate a wide range of geometric shapes; a module, which allows to set properties, parameters and initial conditions and an adaptive mesh generator. The preprocessor module has a graphical interface that allows to create a solution domain visually. The domain is constructed from a set of initial hexahedral blocks (primitives) by their combining and subsequent deformation. The deformation is performed by changing of coordinates of control points of the domain by entering them or reading from a file. The control points of the domain are located on the boundary surfaces of the primitives, form a regular surface mesh and are the basis for the construction of the linear or cubic surface splines. It is possible to generate the curvilinear blocks which are based on the geometries of the surfaces, imported from solid simulation software. The resulting adaptive regular mesh of hexahedrons could be divided into tetrahedrons for applying the finite-volume or finite-element method. The preprocessor can generate finite-volume meshes based on elements centered on the grid point. The vertex-centered control volumes are built around the generated mesh nodes. Such meshes retain adaptation grid lines to geometry borders and allow to obtain solutions of better quality than with meshes generated by ordinary finite-element mesh generators.