What you need from a mesh is both simple (complete coverage of the wetted surface and fluid volume with positive volume cells) and complex (balancing resolution and cell shape metrics). Add to those general needs the specific requirements of your flow solver, and you need meshing software that provides both flexibility and control so that the meshing process is robust and reliable.
That's why Pointwise includes a variety of meshing techniques from automated to manual, from structured to unstructured to hybrid, from 1D to 2D to 3D, from Delaunay to advancing layer to elliptic PDE to overset and high-order, all implemented in a multi-block or multi-zone strategy.
Pointwise's T-Rex (anisotropic tetrahedral extrusion) is an advancing layer technique for extruding regular layers of high-quality (right angle included) tetrahedra from boundaries. The algorithm adjusts to convex and concave regions and colliding extrusion fronts. These anisotropic tetrahedra in the near-wall and near-wake regions are then combined into stacks of prisms or hexahedra. Away from the geometry model, you can use either isotropic tetrahedra or Cartesian hexahedra called Voxels.
Prism and hexahedral layers can also be generated via traditional extrusion methods that follow normal, linear, rotational, or user-defined paths. Tunable controls let you adjust step size, mesh quality, and smoothing of the extruded layers.
Learn strategies to quickly construct a high-quality viscous mesh for a model aircraft propeller. These strategies can be used to accurately capture relevant blade geometry as well as efficiently resolve the surface curvature and boundary layer.
This case study summarizes how a T-Rex hybrid grid showed up to a seven-fold improvement in solution efficiency compared to other approaches in predicting thrust and torque.
Discover how to create unstructured hexahedra quickly on complex geometry using T-Rex (anisotropic tetrahedral extrusion). Best practices for the generation of both surface and volume meshes and troubleshooting techniques are shown.
Clustering to flow features away from the geometry model can be obtained using Sources. These geometric regions (like boxes, cylinders, and spheres) are sketched onto the grid and a length scale is applied. The mesh will be refined to match the length scale within the shape. A special type of source based on a point cloud is used for mesh adaptation. The flow solver provides a length scale at each point in the cloud, which in turn, is used to refine the mesh.
Pointwise's structured quadrilateral and hexahedral grid techniques have been honed continuously since 1984 to generate the best quality grids with the ultimate in control over smoothness, clustering, and orthogonality. Pointwise's elliptic PDE methods iteratively solve Poisson's equation with control functions that can be fine-tuned at any time using the following techniques.
Several formulations of the wall angle and wall spacing constraints are available with the von Lavante-Hilgenstock-White and Steger-Sorenson methods to ensure grids that meet your needs for how transverse grid lines meet boundaries. The elliptic solver methods also feature support for several boundary condition types depending on whether you need the boundary points to remain fixed, slide along the shape, or float with the PDE solution. And the surface formulation of the elliptic PDE methods allows for surfaces to be constrained to the geometry model whether that be a single surface or span a collection of surfaces.
Structured grids with high degrees of orthogonality and clustering control can also be created using Pointwise's hyperbolic PDE and algebraic extrusion methods. The extrusion methods start with one or more structured quadrilateral surface grids and extrude hexahedral volume grids. All of the extrusion methods also can be applied to 2D grids and surface grids constrained to the geometry model. In the latter case, the mesh marches across the entire geometry model, from one surface to the next.
The hyperbolic method is especially well suited for CFD solvers that use overlapping grids but contains features to extrude multi-block abutting grids as well. In other words, a point to point interface can be maintained between adjacent abutting blocks.
In this video you will see a diffusing serpentine inlet used to demonstrate some of the more advanced structured gridding techniques available in Pointwise.
This case study describes how structured grids can provide the high accuracy and low cell count required for marine applications.
Using Pointwise's integration with two overset grid assembly (OGA) software tools, you can now execute the entire overset assembly process, sometimes known as hole cutting, from within a single software product instead of using a chain of other tools. From Pointwise you can launch OGA software for selected grids, import the results of the OGA computations, and visualize the resulting parameters of interest for your overset grid.
Pointwise's overset grid assembly capabilities include:
Pointwise is on the leading edge of research and development in the area of high-order mesh generation to support high-order flow solvers. Any linear mesh can be elevated up to polynomial degree 4. Most importantly, the surface mesh cells will be curved to match the shape of the geometry model. That curvature is then blended into the volume mesh's interior in order to prevent cell crossing.
This case study describes how Pointwise supports the use of overset grids for advanced CFD applications.
This video demonstrates the process of generating overlapping grids, setting up and executing Suggar++, and exporting the domain connectivity information all from within Pointwise. We demonstrate an overset flow simulation using the Caelus CFD solver.
This video shows how Pointwise overcomes the challenges associated with degree elevation of linear elements: boundary conformance and curving of high aspect ratio cells.
Your verification and validation activities have resulted in best practices for the type of mesh needed to get a converged and accurate CFD solution. Those best practices included thresholds on various mesh metrics. That is why Pointwise includes tools that provide both global and local views of mesh quality. Cutting planes can be used to dissect the mesh to see the interior, and graphical tools can be used to zoom in on the cells with the minimum and maximum metric values.
Rules are a global technique for proactively monitoring mesh quality. You can define the acceptable values of any metric. Then, as you are creating the mesh, pressing one button at the top level of the interface will immediately display all grids that violate the rule.