Advanced Boundary Cartesian Meshing Technology in Solidworks Flow Simulation

SolidWorks ® Flow Simulation is an intelligent, easy-to-use computational fluid dynamics (CFD) program that facilitates the work of design engineers who use SolidWorks 3D CAD software for design creation. This paper details the approach and theory behind the Cartesian mesh generation used in SolidWorks Flow Simulation. Detailed explanation and examples will support how this choice of mesh generation algorithm enables SolidWorks Flow Simulation to offer a best-in-class CFD solution centered upon simplicity, speed, and robustness. ABSTRACT For the numerical simulation of Navier-Stokes equations, the choice of the mesh type plays a significant role. Comparative calculations on different mesh types illustrates that the best simulation precision, characterized by minimum Local Truncation Error (LTE), is obtained on Cartesian meshes. For the boundary representation, the Immersed Boundary (IB) approach, which does not require a boundary-conforming mesh, is used. Use of Cartesian meshes together with the Immersed Boundary approach makes it possible to efficiently minimize approximation errors, build operators with good spectral properties so that robustness of method is guaranteed, speed up the process of grid generation, and make grid generation robust and flexible. Many other CFD methods require a mesh that fits the boundaries of the computational domain and often complex internal geometries. The body-fitted grid generation used is time-consuming, often requiring manual intervention to modify and clean-up of the CAD geometry as a prerequisite. Implementing the IB approach efficiently in SolidWorks Flow Simulation requires resolving a number of issues: approximation of the governing equations in cut-cells that contain the solid-fluid interface, capture of boundary layers effects irrespective of boundary layer thickness using a Two-Scale Wall Functions (2SWF) approach automatic mesh generation with automatic detection of initial mesh settings (octree-based mesh structure), and Solution Adaptive Refinement (SAR). Test cases given in this paper represent a small selection of our validation examples that illustrate the precision of the IB approach and the flexibility of SolidWorks Flow Simulation meshing technology in the wide range of industrial examples of geometry and physical formulations.