Enhanced Viscous Mesh Generation with Metric-Based Blending

In this work we describe a unified approach that blends the best characteristics of both a near body pseudo-structured boundary-layer (BL) and generalized anisotropic metric approaches. Specifically, near-body physics with anisotropy are resolved using an a priori pseudo-structured process and off-body or field features are resolved using an adaptive generalized approach. In particular the metric field of the adaptive approach is derived from the BL region of the pseudo-structured approach. The derived metric is based on local aspect ratio and geometry. This metric is then blended from the BL region into the overall field to allow for a smooth transition to the generalized field. The result is a flexible and optimal overall mesh generation process that can be used with or without adaptation. Metric-based formulations for quality functions and other geometric quantities require for mesh generation are presented. Results are presented that demonstrate the overall approach in the context of blending between the near body pseudo-structured region and the outer tetrahedral field region. These results point out that the metric-based transition can be used to improve mesh quality and density for configurations with anisotropic surface meshes and BL regions that do not reach outer region length scale.