Segregated EMP Flow Solver

The Segregated EMP Flow solver controls the solution update for the Eulerian Multiphase (EMP) model. It is responsible for solving the velocity field for each individual phase and the overall pressure solution.

For more information, see Eulerian Multiphase Model Reference.

The Segregated EMP Flow solver incorporates the following:

Segregated EMP Flow Solver Properties

The properties in the Expert category are for a temporary debug situation, at the expense of simulation accuracy and higher memory usage. Do not change any of these properties unless you are thoroughly familiar with the discretization techniques used in Simcenter STAR-CCM+.

Reconstruction Frozen
When On, Simcenter STAR-CCM+ does not update reconstruction gradients with each iteration, but rather uses gradients from the last iteration in which they were updated. Activate Temporary Storage Retained in conjunction with this property. This property is Off by default.
Reconstruction Zeroed
When On, the solver sets reconstruction gradients to zero at the next iteration. This action means that face values used for upwinding (Eqn. (905)) and for computing cell gradients (Eqn. (917) and Eqn. (918)) become first-order estimates. This property is Off by default. If you turn this property Off after having it On, the solver recomputes the gradients on the next iteration.
Temporary Storage Retained
When On, Simcenter STAR-CCM+ retains additional field data that the solver generates during an iteration. The particular data retained depends on the solver, and becomes available as field functions during subsequent iterations. Off by default.
Interaction Force Storage Retained
Allows you to retain the information that is stored for each phase interaction force model at the end of the iteration. These quantities become available as field functions during subsequent iterations.

You can use this option when you want to visualize the phase interaction forces, such as drag, turbulent drag, lift, virtual mass, and wall lubrication.

Freeze Flow
When On, the solver does not update any quantity during an iteration. Use this for debugging purposes, or to keep one set of equations fixed while you solve another set. Off by default.

Phase Coupled Velocity Solver for Multiphase Flow

The Phase Coupled Velocity solver solves the discrete conservation equations to obtain the intermediate velocity field for all the phases. The corresponding Phase Coupled Velocity Solver node controls the under-relaxation factor and algebraic multigrid parameters for the Eulerian phase momentum equations.

The equations for velocity component correction are solved for all phases simultaneously. One advantage of this solver is that it permits greater robustness in solving multiphase flows with high levels of phase interaction.

Phase Coupled Velocity Solver Properties

Implicit Under-Relaxation Factor

Improves stability and convergence of the linear system by using the relaxation factor to increase diagonal dominance of the matrix.

The default value is 0.7.

Explicit Under-Relaxation Factor

This property specifies the multiplier that is applied to the provisional increment of the solution. Sharing the relaxation between implicit and explicit factors can be used to improve performance.

The default value is 1.0.

Overall Relaxation Factor

The product of the two under-relaxation factors (that is, Implicit Under-Relaxation Factor times Explicit Under-Relaxation Factor). This (read-only) value is a guide to the combined effect of the relaxation.

See Setting the Solver Parameters.

Pressure Solver for Multiphase Flow

The Pressure solver controls the under-relaxation factor and algebraic multigrid parameters for the pressure correction equation.

Pressure Solver Properties

Under-Relaxation Factor
At each iteration, this property governs the extent to which the newly computed solution supplants the old solution. The default value is 0.3.
Pressure Reference Location

Lets you choose between using the automatic algorithm of Simcenter STAR-CCM+ for the reference location or providing it manually. For more information, see Setting Reference Values..

Automatic Selection
Simcenter STAR-CCM+ sets the reference location at the cell that is next to the boundary face with the smallest X, Y, Z location in the domain.
User Specified

The Pressure Reference Points node is added. Use this method to add one or more reference locations depending on the number of non-contiguous regions.