Generation of structured block boundary grids

In external flow hydrodynamics, the computation domain is typically bounded internally by a given surface shape, but externally the domain border can be conveniently chosen. After subdivision of the domain into several blocks, only a few block faces are located on the specified surface shape; the other block faces are specified by their edges only. The generation of a grid on a block face, given by its edges only, is therefore a frequently encountered task. In this paper, we present a grid generation package for structured grids on such block faces, which are arbitrarily positioned in space but only moderately curved usually. For generating a grid on such faces a quasi 2D grid approach is not only more efficient but also gives better results than a general 3D surface grid generation technique. One of the grid point coordinates is obtained with an algebraic interpolation technique applied in a rotated coordinate system that minimizes its value. The two remaining coordinates are obtained with algebraic, hyperbolic or elliptic methods of 2-D grid generation, which include the influence of the third coordinate.