Finite Element Solvers Reference

Common Properties

The following properties are common to most finite element solvers:

Solver Method

Allows you to choose the type of solver that Simcenter STAR-CCM+ uses to compute the solution. Available only for the FE Magnetic Vector Potential solver, the Finite Element Solid Energy solver, and the Harmonic Balance Fe Magnetic Vector Potential solver. All other finite element solvers automatically use the direct solution approach.

Depending on the selected method, Simcenter STAR-CCM+ activates the relevant solver controls:

Method	Activated Controls
Direct Simcenter STAR-CCM+ computes the solution using a sparse direct solver. For large cases, a direct solution approach can result in large memory and time requirements, especially for parallel execution. For these cases, you can choose the iterative solution approach.	Direct > Sparse Direct Solver For information on the direct solver properties, see FE Sparse Direct Solver Reference.
Iterative Simcenter STAR-CCM+ computes the solution using an iterative solver.	Iterative For information on the iterative solver properties, see FE Iterative Solver Reference.

Solver Frozen

When On, the solver does not update any quantity during an iteration. It is Off by default. This is a debugging option that can result in non-recoverable errors and wrong solutions due to outdated values. When activated, it causes all those actions to be skipped which are typically orchestrated by a solver, such as allocating storage, updating boundary conditions and gradients, triggering the computations to assemble the linear system (such as the computation of source terms for the transport equation, which may implicitly trigger dependent computations), computing corrections for the solution variable, removing storage, and so on.

A safer way to prevent the solver from applying any corrections to the transport variable is to set AMG Linear Solver > Max Cycles to zero. In that case, storage is managed properly and boundary conditions (and in some cases gradients) are updated, but the computation of corrections is skipped. Hence, the savings in CPU time is slightly smaller but there is no additional risk of non-recoverable errors.

If a non-recoverable error associated with missing or uninitialized storage is encountered when using Solver Frozen, deactivate Solver Frozen during solution intitialization for at least one iteration with the Temporary Storage Retained option activated before re-activating the Solver Frozen option. There still exists a risk of using outdated values somewhere without any indication.

Temporary Storage Retained

When activated, Simcenter STAR-CCM+ retains the residuals computed at each iteration and stores them as field functions.

Norm Type

Specifies the method that Simcenter STAR-CCM+ uses for calculating the norm of the residual and the solution increment. The available options are Max Norm, L1 Norm, and Euclidean Norm (see Residual Norms).

When the Normalization Option for the residual and the solution increment monitors is set to Auto, Simcenter STAR-CCM+ displays normalized values, that is, the residual and the solution increment norms are divided by the norm values computed at the first solver iteration.

[Energy Increment]

The name of this property depends on the corresponding finite element solver:

Solver	Property Name
Magnetic Vector Potential	Energy Norm
Solid Stress	Strain Energy
Finite Element Solid Energy	Thermal Potential

When activated, Simcenter STAR-CCM+ adds a monitor for the energy increment, which can be visualized in the Residuals plot.

The energy increment is calculated according to Eqn. (4838). When the Normalization Option for the energy monitor is set to Auto, the energy increment is normalized with respect to the energy increment computed at the first solver iteration.

Right-Click Actions

Restore Default Settings

When selected, restores the solver to its default settings, that is, the settings that the solver has when it is created from a new simulation.