Prismatic mesh generation using minimum distance fields

Abstract Anisotropic prismatic/strand meshes are often used to capture viscous boundary layer effects in Reynolds Averaged Navier Stokes (RANS) simulations of high Reynolds number flows. This paper describes a new algorithm for generation of prismatic meshes using the minimum distance field of the surface tessellation. The algorithm starts with initial point placement using both the direction of best visibility and the direction to the closest point on the minimum distance iso-surface. Initial point placement is followed by a constrained smoothing operation based on an elastic spring analogy. The constraints ensure movement of nodes is restricted to the iso-surface of the distance field and within the region of visibility. Simulations are performed using a dual-mesh infrastructure, where the prismatic meshes transition to a Cartesian background mesh a short distance from the wall. This overset mesh system is processed by a domain connectivity method to establish connections between self-intersecting strand meshes and strand/Cartesian mesh systems. Mesh and flow simulation results are presented for test cases of varying complexity.

[1]  Rainald Löhner,et al.  On the 'most normal' normal , 2007 .

[2]  Aaron Katz,et al.  High-Order Methods for Turbulent Flows on Three-Dimensional Strand Grids , 2016, J. Sci. Comput..

[3]  Scott R. Kohn,et al.  Large scale parallel structured AMR calculations using the SAMRAI framework , 2001, SC.

[4]  R. Löhner,et al.  Progress in grid generation via the advancing front technique , 2005, Engineering with Computers.

[5]  Adrien Loseille,et al.  Robust Boundary Layer Mesh Generation , 2012, IMR.

[6]  Frédéric Alauzet,et al.  Metric-Aligned and Metric-Orthogonal Strategies in AFLR , 2017 .

[7]  Yannis Kallinderis,et al.  Hybrid Prismatic/Tetrahedral Grid Generation for Viscous Flows Around Complex Geometries , 1996 .

[8]  Vipin Kumar,et al.  A Fast and High Quality Multilevel Scheme for Partitioning Irregular Graphs , 1998, SIAM J. Sci. Comput..

[9]  Aaron Katz,et al.  High-order flux correction/finite difference schemes for strand grids , 2015, J. Comput. Phys..

[10]  nbsp,et al.  Overview of RCAS Capabilities, Validations, and Rotorcraft Applications , 2015 .

[11]  François Bay,et al.  An innovative strategy to create equivalent elements for modelling assembly points in joined structures , 2014 .

[12]  Andrew M. Wissink,et al.  Simulation of Complex Geometries Using Automatically Generated Strand Meshes , 2018 .

[13]  Andrew M. Wissink,et al.  Application of strand meshes to complex aerodynamic flow fields , 2010, J. Comput. Phys..

[14]  John P. Steinbrenner.  Construction of Prism and Hex Layers from Anisotropic Tetrahedra , 2015 .

[15]  Frédéric Alauzet,et al.  Parallel anisotropic 3D mesh adaptation by mesh modification , 2006, Engineering with Computers.

[16]  David L. Marcum.  ADVANCING-FRONT/LOCAL-RECONNECTION (AFLR) UNSTRUCTURED GRID GENERATION , 1998 .

[17]  Forrester T. Johnson,et al.  Modi cations and Clari cations for the Implementation of the Spalart-Allmaras Turbulence Model , 2011 .

[19]  William G. Bousman,et al.  Flight Testing the UH-60A Airloads Aircraft , 1994 .

[20]  Frédéric Alauzet,et al.  A decade of progress on anisotropic mesh adaptation for computational fluid dynamics , 2016, Comput. Aided Des..

[21]  Rohit Jain,et al.  Recent Advancements in the Helios Rotorcraft Simulation Code , 2016 .

[22]  Paul G. Tucker,et al.  Differential equation-based wall distance computation for DES and RANS , 2003 .

[23]  Dimitri J. Mavriplis,et al.  Unstructured Mesh Solution Techniques using the NSU3D Solver , 2014 .

[24]  D. Jung,et al.  Octree-based hierarchical distance maps for collision detection , 1996, Proceedings of IEEE International Conference on Robotics and Automation.

[25]  P. Spalart.  A One-Equation Turbulence Model for Aerodynamic Flows , 1992 .

[26]  Zhi Wang,et al.  Accelerating advancing layer viscous mesh generation for 3D complex configurations , 2017 .

[27]  Jayanarayanan Sitaraman,et al.  Wall distance search algorithm using voxelized marching spheres , 2013, J. Comput. Phys..

[28]  Andrew M. Wissink,et al.  Progress in Strand Mesh Generation and Domain Connectivity for Dual-Mesh CFD simulations , 2017 .

[29]  Andrew M. Wissink,et al.  Maneuvering Rotorcraft Simulations Using CREATE A/VTMHelios , 2016 .

[30]  Beatrice Roget,et al.  Development and validation of a multi-strand solver for complex aerodynamic flows , 2017 .

[31]  Vinod K. Lakshminarayan,et al.  Sensitivity of Rotorcraft Hover Predictions to Mesh Resolution in Strand Grid Framework , 2017, AIAA Journal.

[32]  Maximillian Tomac,et al.  Towards Automated Hybrid-prismatic Mesh Generation , 2014 .

[33]  R. Löhner,et al.  Generation of viscous grids at ridges and corners , 2009 .

[34]  Andrew M. Wissink,et al.  On Strand Grids for Complex Flows , 2007 .

[35]  J. Bonet,et al.  An alternating digital tree (ADT) algorithm for 3D geometric searching and intersection problems , 1991 .

[36]  Shahyar Pirzadeh,et al.  Unstructured Viscous Grid Generation by Advancing-Layers Method , 1993 .

[37]  Robert Haimes,et al.  MOSS: multiple orthogonal strand system , 2014, Engineering with Computers.

[38]  Frédéric Alauzet,et al.  A Closed Advancing-Layer Method with Changing Topology Mesh Movement for Viscous Mesh Generation , 2013, IMR.

[39]  David L. Marcum,et al.  Mixed Element Type Unstructured Grid Generation for Viscous Flow Applications , 1999 .