技术支持知识库

Solver Solutions

1249: Solution number is out of range

You compute a distributed parametric sweep on a cluster. When processing the results some values are missing or you get errors such as "The solution number is invalid" or "Solution number is out of range". This issue...
Version: 5.3a - Platform: All Platforms

1245: Improving runtimes for transient models with step changes in loads

I am solving a transient model which has loads that change instantaneously in time, but the solver is taking a very long time to compute the solution. When solving a transient model, be aware that the default behavior...
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1240: Manually Setting the Scaling of Variables

The default behavior of the software is to assume a different scaling for each set of variables in your model. These scale factors are by default automatically determined, but sometimes may need to be manually...
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1213: Manually setup the geometric multigrid solver

The geometric multigrid solver accelerates the convergence of the iterative solver by solving the finite element problem on a series of meshes rather than a single one. The multigrid algorithm starts with the initial...
Version: All versions - Platform: All Platforms

1172: Solving 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: All versions - Platform: All Platforms

1118: Resolving time-dependent waves

I am solving a time-dependent wave-type problem, what mesh and solver settings should I adjust for better accuracy and runtimes? The accuracy of a time-dependent model solving for electromagnetic, acoustic,...
Version: All versions - Platform: All Platforms

1102: Structural Contact Modeling Guidelines

This article contains guidance for solving models that include structural contact, and the procedures that should be followed to achieve a converged solution. Background Structural contact modeling is a highly...
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 parallelism and distributed-memory parallelism (cluster support)....
Version: All versions - Platform: All Platforms