Improved Advancing Front Mesh Algorithm with Pseudoislands as Internal Fronts

Abstract

This paper presents an alternative implementation of the advancing front method for generating two-dimensional triangular unstructured meshes for finite-element applications. After initializing the front along the boundaries, internal fronts, called pseudoislands, are created inside the domain where a node-spacing function condition is met. When the element creation starts, several disjoint fronts are made active, one for each pseudoisland, and the temporal order of creation of the elements follows a smaller to bigger size sequence in an inside-to-outside propagation of the front. Postprocessing routines are available for enhancing the mesh quality. A test case for an idealized geometry shows the effectiveness of the method with high node-spacing function gradients. Several discretizations of a light detection and ranging (LIDAR) derived digital elevation model are compared for demonstrating the improvement of the new advancing front version with respect to the standard version in real applications. Finally, one of the meshes obtained with pseudoislands is used in a wet and dry tide modeling study, showing a superior resolution of the sharp bathymetric gradients and an improvement on the simulation of the wetting and drying process.