Under Numerics you can set the equation solver for your simulation, change the convergence settings or choose the time integration scheme for transient dynamic simulations. These settings mainly influence the stability and efficiency of your simulation run, but also the quality of the results may depend on these settings.
In most cases the standard settings should be a good choice and should not be changed without reason.
However, all numerical setting are made available for users to have full control over the simulation. These settings are divided into three categories:
All properties regarding the iterative solvers of velocity and pressure equations are set here. Relaxation factors, residual controls, and solver-specific tweaks are among these settings. However, depending on the solver (e.g. PIMPLE, PISO, …), these settings will be adjusted. For each field, a Help message is provided on the platform.
In this part, linear solvers used in computing each variable could be chosen separately. Upon choosing a solver, a set of preconditioners/smoothers and their tolerances become available. To assist with selecting the best solver, a Help message is provided for each field.
These schemes determine how each term in the governing equations should be discretized. Schemes categorized in the following groups:
Generally, for Numerical Schemes the default selections are the best choice and require no changes.