Base de connaissances du support

Manually setup the geometric multigrid solver

Solution numéro: 1213 Versions: Toutes les versions

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 ...

---

Solving time dependent models with inconsistent initial values

Solution numéro: 1172 Versions: Toutes les versions

A common mistake when setting up transient models is to have initial conditions that are inconsistent with the loads and boundary conditions. This occurs most often when running transient fluid flow studies, but the ...

---

Improving Convergence of Nonlinear Stationary Models

Solution numéro: 103 Versions: Toutes les versions

Stationary (time-invariant) models with nonlinearities may converge very slowly. A nonlinearity can be introduced into the model either in the governing equation, or by making any of the material properties, loads, or ...

---

Improving convergence in nonlinear time dependent models

Solution numéro: 1127 Versions: Toutes les versions

When I look at the Solver Log of a time dependent model, I see that the NLFail column has non-zero entries: Step TimeStepsize Res JacSolOrderTfailNLfailLinErrLinRes 0 0-out 23208e-14 3.5e-15 ...

---

Structural Contact Modeling Guidelines

Solution numéro: 1102 Se réfère à: MEMS Module, Structural Mechanics Module Versions: Toutes les versions

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 non ...

---

COMSOL and Multithreading

Solution numéro: 1096 Versions: Toutes les versions

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). Shared ...

---

BDF, Generalized Alpha, and Runge-Kutta Methods

Solution numéro: 1062 Versions: Toutes les versions

What numerical methods are available when using a Time-Dependent Solver? What are their relative benefits and when should I use them? The Time-Dependent Solver offers three different time stepping methods: The ...

---

Error: "Out of memory"

Solution numéro: 1030 Versions: Toutes les versions

I get an error message, that contains the words Out of memory, for example: Out of memory during LU factorization. or Out of memory during assembly # Background Before resolving this issue, you should go through ...

---

Running COMSOL® in Parallel on Clusters

Solution numéro: 1001 Versions: Toutes les versions

This solution describes how you enable distributed parallelization (cluster jobs) in COMSOL Multiphysics®. COMSOL supports two mutual modes of parallel operation: shared-memory parallel operations and distributed ...

---

My Flux Calculation Seems Wrong

Solution numéro: 973 Versions: Toutes les versions

I am solving a diffusion-like problem in COMSOL Multiphysics and discovered that boundaries that are defined with insulation/symmetry conditions have an integrated value of the normal component of the flux that is far ...

---