3.8 Fiber Model Solution Controls

To access the Fiber Solution Controls dialog box, go to

Models Fiber-Controls Edit...

Figure 3.8.1: Fiber Solution Controls Dialog Box

The Fiber Solution Controls dialog box allows you to set common solution parameters for the fiber equations and their coupling with the surrounding fluid.

Solve   is used to enable and disable the solution of the fiber equations for Momentum (Equation  2.2-4), Energy (Equation  2.2-11), and Species (Equation  2.2-1). When switching off the solution of one of these equations, it is not computed for all fibers defined in your model.

Discretization   provides a drop-down list where you can assign to each of the fiber equations one of three different discretization schemes explained in Section  2.3.

Underrelaxation   contains all under-relaxation factors for all fiber equations that are being solved in the continuous fiber model. See Section  2.3.1 for additional background information and see Section  2.10 for how to make use of under-relaxation factors in your solution strategy.

Convergence Criterion   is used to stop the fiber iterations when the residuals of all fiber equations are below the prescribed criteria. You can define a separate convergence criterion for every fiber equation.

Check Convergence   must be turned on if you want to compare the residuals of the fiber equations with the Convergence Criterion. If you turn this option off, the given number of fiber iterations will be computed.

Relative Residuals   are used to compute the change of the residual of two subsequent iterations relative to the residual of the last iteration by applying Equation  2.5-3. The result of this is compared to the Convergence Criterion to check whether convergence has been achieved.

Iterations   defines the number of Fiber Iterations performed every time the fiber equations are updated.

Reporting Interval   sets the number of fiber iterations that will pass before the residuals will be printed.

You can reduce the output to the last fiber iteration by specifying Reporting Interval as 0. This is recommended when performing a solution that is coupled with the surrounding flow.

Number of FLUENT Iterations per Fiber Computation   sets the number of ANSYS FLUENT iteration before the fiber equations are updated in a solution that is coupled with the surrounding flow.

Source Term Underrelaxation   factor is used to under-relax the fiber source term exchange to the surrounding fluid. In a converged solution this value does not influence your predictions.

For additional information on how to set and choose values for the options in the Fiber Solutions Control dialog box, see Section  2.10.