Thermal - Advanced Options

The Advanced tab of the Thermal dialog box allows you to set convergence options for the active transient thermal study.

To access the Advanced thermal options dialog box, right-click the icon of a thermal study in the Simulation study tree and select Properties. Then click Advanced at the bottom of the dialog box to open the Advanced tab.

Tolerance Options

Sets convergence parameters.

Convergence tolerance Relative temperature tolerance used for equilibrium convergence.
Under-relaxation factor Controls the rate at which the solution is changing during iterations. Select Automatic to use a default value computed by the program, or select Fixed to directly specify a value. A value of 1 allows the solution to move faster but may not lead the nonlinear solution to convergence.

Smaller values (less than 1) for the under-relaxation factor keep the solution close to the initial guess and enhance the chances of solution convergence. This is especially helpful for radiation problems.

The advanced thermal options are integrated in both the Direct sparse and FFEPlus solvers. They have similar function with the advanced nonlinear options: Convergence tolerance and Singularity elimination factor.