Defining Energy Equation Controls

You can define controls to fine-tune the energy equation solver.

Important: These controls are intended for expert users.

Before you begin:
See Also
About Equation Controls
  1. From the Linear solver options, select one of the following techniques for calculating the pre-conditioner matrix:
    OptionDescription
    ILU-BiCGStab Calculates the pre-conditioner matrix using the incomplete lower-upper factorization bi-conjugate gradient stabilized method.
    DS-FGMRES Calculates the pre-conditioner matrix using the diagonally scaled flexible generalized minimum residual method.
    ILU-FGMRES Calculates the pre-conditioner matrix using the incomplete lower-upper factorization flexible generalized minimum residual method.

    The ILU-BiCGStab linear solver is recommended for most simulations.

  2. Enter a value for the Iteration limit, which is the maximum number of iterations for the linear solver.
  3. Enter a value for the Convergence check frequency, which is the interval (in linear iterations) to check linear convergence.
  4. Enter a value for the Linear convergence limit, which is the point at which the iterative solver stops.

    The iterative solver stops when the relative residual norm of the system of equations and the relative correction of the solution norm fall below this convergence limit.

  5. If you selected the ILU-FGMRES or DS-FGMRES linear solver, enter a value for the Number of restart vectors.

    The number of restart vectors is the number of times the solution is projected into a subspace before the subspace is rebuilt.

  6. If you defined solid physics in your simulation, specify how often the linear solver computes the energy of the solids with respect to the energy of the fluids from the Solid energy subcycling options:
    OptionDescription
    None Computes the energy of the solids as often as the energy of the fluids.
    Specified Enables you to specify how often the linear solver computes the energy of the solids with respect to the energy of the fluids.

    For more information about defining solid physics, see Defining the Solid Physics of a Flow Simulation.