Improved algorithm for unstructured quadrilateral meshing

A two-dimensional algorithm and a software code for unstructured quadrilateral meshing were developed. The algorithm is based on the Q-Morph algorithm proposed by S. Owen in 1998 and is classified as an indirect advancing front method for quadrilateral unstructured mesh generation. The meshing procedure involves a preliminary triangulation of the underlying domain followed by the transformation of the resulting triangles into quadrilateral cells. The input data are the coordinates of the boundary nodes. The algorithm performs automatically and does not modify the boundary nodes. The resulting mesh is all-quadrilateral if the boundary of the domain consists of an even number of edges. If the number of edges is odd, a triangular cell appears in the mesh. The code based on the algorithm can be exploited as an independent mesh-generating module.