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Solver Solutions

1172: Running time dependent CFD simulations

A common mistake when running transient fluid flow studies with COMSOL Multiphysics is to start the simulation with conflicting boundary conditions. Let's take a simple example to illustrate this issue. We will compute...
Version: All versions - Platform: All Platforms

1157: Improve the performance of contact models built in version 4.0a or...

I have an old contact model that was built in COMSOL Multiphysics 4.0a or earlier. Now that I am using a later version of COMSOL Multiphysics, how can I take advantage of the better stability of this version in my...
Version: All versions - Platform: All Platforms

1127: Improving convergence in nonlinear time dependent models

My time dependent model solves without any problem as long as I use only linear materials. How can I get it to converge with a nonlinear material?   When a time dependent solver has trouble converging, its default...
Version: 4.2 - Platform: All Platforms

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

1102: Improve the stability of your contact model

In this article, you can find both general tips of how to improve convergence in your contact model and how to change solver settings of older models. ## Some General Contact Tips * The choice of source and...
Version: All versions - Platform: All Platforms

1096: COMSOL and Multithreading

This solution describes how COMSOL takes advantage of multicore computers. COMSOL supports two mutual modes of parallel operation: shared-memory parallel operations and distributed-memory parallel operations, including...
Version: All versions - Platform: All Platforms

1095: Error: Cannot open native file

I get an error message that looks like: The following feature has encountered a problem: -Feature: Stationary Solver 1 (sol/s1)-Error: Cannot open native file. The problem is related to a Windows user name that...
Version: 4.1,4.2,4.2a - Platform: All Platforms

1062: BDF vs. Generalized Alpha time discretization

I usually use the *BDF* time stepping method. But I have certain examples where the Generalized alpha method is much better. What numerical method is used when I choose the *Generalized alpha* method? Is the...
Version: All versions - Platform: All Platforms

1039: A declared function in COMSOL Multiphysics model seems to give...

I have a COMSOL Multiphysics model that solves for V. In the source term (right-hand side) of the PDE, I use an analytic function of V, f1(V), that I have defined in the Options->Functions dialog box. I do not get...
Version: 3.5a - Platform: All Platforms