OPTIMIZATION STRATEGIES IN UNSTRUCTURED MESH GENERATION

We propose a new optimization strategy for unstructured meshes that, w hen coupled with existing automatic generators, produces meshes of hig h quality for arbitrary domains in 3-D. Our optimizer is based upon a non-differentiable definition of the quality of the mesh which is natu ral for finite element or finite volume users: the quality of the wors t element in the mesh. The dimension of the optimization space is made tractable by restricting at each iteration, to a suitable neighbourho od of the worst element. Both geometrical (node repositioning) and top ological (reconnection) operations are performed. It,turns out that th e repositioning method is advantageous with respect to both the usual node-by-node techniques and the more recent differentiable optimizatio n methods. Several examples are included that illustrate the efficienc y of the optimizer.