|Title||COMSOL Multiphysics – Constructing High Quality Computational Meshes|
|Abstract||COMSOL Multiphysics is a software package for simulation of various physical phenomena, covering a broad area of application, from classical Structural Mechanics, Electromagnetics, Heat Transfer, Acoustics, and Fluid Dynamics to more specialized areas such as Plasma physics, Geomechanics, or the physics for Semiconductors, Batteries, and Fuel cells. In a majority of these cases, the problems boil down to a system of PDEs solved by the Finite Element Method (FEM).
The Math & Computer Science group at COMSOL is responsible for what is traditionally called pre-processing. The goal is to convert a geometry description in some form to high quality computational mesh consisting of (for example) simplex or hexahedral elements, and which is suitably resolved to represent the physics solved for. I will try to give some insight into the challenges we face and problems we try to solve.
The classical geometry input is a CAD drawing that can have thousands of faces edges and typically has slightly misaligned parts resulting in small gaps, slivers etc., which are disastrous for the mesh generation. This calls for robust computer aided (or automatic) geometry analysis and simplification.
More recently, it has become more common to have a geometry that is not drawn, but rather scanned by some imaging technique and converted into a surface mesh. Such geometries are often of biological origin (blood vessels, bones, etc) but can also be from subsurface scans, or laser scanned technical devices, where the original CAD drawing is not available. These classes of geometries constitute another type of challenge.