Support Knowledge Base

1118: Resolving time-dependent waves

I am solving a time-dependent wave problem, but the solution does not look quite right. I was expecting a smooth propagating waveform but see mostly noise.   The accuracy in a model solving an equation for...
Version: 4.2 - Platform: All Platforms

1103: Frequency-dependent meshing

I am solving a wave equation over a wide range of frequencies. At the highest frequencies, I need a very fine mesh in order to resolve the wavelength. For lower frequencies, I am happy with a coarser mesh. How do...
Version: 4.1,4.2 - Platform: All Platforms

1048: Error: 9040 IllegalArgumentException

When I open a 3D model from the model library, or create a a 3D object, for example by extrusion of a circle, or try to view a 2D mesh, I get an error message that includes any of the following strings: Error: 9040...
Version: 3.5a - Platform: All Platforms

1010: Error: System matrix is zero

I get the error message "System matrix is zero". What is the problem? The problem could be that you only made surface meshes on a 3D object, for example with the mapped mesh. If there are no...
Version: 3.5a,4.0,4.0a,4.1,4.2,4.2a - Platform: All Platforms

Why do the currents in my metal look strange? How can I get a realistic solution at high frequencies? Not resolving the skin depth is one of the more common modeling mistakes in AC and RF applications. Luckily, in most...
Version: 4.0,4.0a,4.1,4.2 - Platform: All Platforms

This solution describes how you enable distributed parallelization (cluster jobs) in COMSOL. COMSOL supports two mutual modes of parallel operation: shared-memory parallel operations and distributed-memory parallel...
Version: 4.0,4.0a,4.1,4.2,4.2a - Platform: All Platforms

983: Error: Internal Error in Geometry Decomposition (General)

Why do I get the error message “Internal error in geometry decomposition”? [reference id="1089"]Note: if you use COMSOL 4 and have any of the CAD import products, please refer to solution 1089.[/reference] This...
Version: 3.5a,4.0,4.0a,4.1,4.2,4.2a - Platform: All Platforms

902: Thin film approximation, contact resistance

In modeling of transport by diffusion or conduction in thin layers, we often encounter large differences in dimensions of the different subdomains in a model. If the modeled structure is a so-called sandwich...
Version: 3.5a,4.0,4.0a,4.1,4.2,4.2a - Platform: All Platforms

875: What does degrees of freedom (DOFs) mean in COMSOL Multiphysics?

What does degrees of freedom (DOFs) mean in COMSOL Multiphysics? The solution time and memory requirements are strongly related to the number of degrees of freedom in the model. It is often desirable to be able to...
Version: 3.5a,4.0,4.0a,4.1,4.2 - Platform: All Platforms

Can COMSOL Multiphysics import topological data, meshes, and images? Topological Data, GIS, Digital Elevation Models (DEM) If you have topological information saved in the DEM format, you can bring it into your COMSOL...
Version: 4.2a - Platform: All Platforms