Meshing Tools for Open Source CFD: A Practical Point of View

This document is part of the project Tools for Large Scale Computational Fluid Dynamics, LSCFD. The project is managed by CSC – IT Center for Science Ltd. (CSC) and partially funded by Tekes (Finnish Funding Agency for Technology and Innovation). The main objective of the project is to promote the use of large scale CFD in Finland. The project will support, enhance and document the use of selected open source CFD solvers. Mesh generation is an essential part of the solution procedure which often consumes the most of the human resources.In this report three different tools or utilities for creating a computational mesh for OpenFOAM CFD code are presented: SALOME, gmsh and OpenFOAM snappyHexMesh. All these software are open source. The point of view of this study is on practical side, i.e. usability, software ergonomics and ability to produce high quality mesh are emphasised instead of meshing algorithms. The same study and test procedure has been applied for all three tools. Software functionality is studied based on soft-ware manuals and by using the software. One common, industrial meshing test case was selected. With this test case the usability of these tools could be tested into some extend and compared. In the last section there is presented some comments about these tools and in general about the development of open source mesh generation tools. A typical pre-processing (mesh generation) process for CFD or FEM computation is described in general. In this process description the domain geometry is taken as is from the design system (typically CAD system) and all the modifications are done during the pre-processing process. The study indicates that there are good open source software components already available for CFD pre-processing, but at least the tested implementations haven’t been completely successful in using them and implementing a really user friendly, intuitive and industrial strength pre-processing tool. None of the tested tools or methods can be recommended for general industrial use as such. More development needs to be done for these meshing tools to reach a level where the whole process is efficient and produces high quality results. But the development seems to be on right path and all the elements for good progress are already available.