Flow Regions Reference

This section details the conditions that are required for each region type that is supported by the Flow models. In addition, information is provided about the values for each region type.

Region conditions and values are elected by the region type, and/or by methods selected in corresponding nodes in the Conditions node.

Note	Region types that do not require setting any conditions or values are not listed.

Fluid Region

Mass Source Option (not for multi-component or VOF flows)

Allows you to add additional mass to the flow domain.


Method	Corresponding Value Nodes
Off	None.
On Adds a specified mass source to the continuity equation, see $S_{u}$ in Eqn. (664).	Mass Source Scalar profile value to specify the mass source. The dimensions of the mass source term are mass per volume per time. Mass Source Pressure Derivative For a Mass Source that is a function of pressure, sets the derivative of the mass source with respect to pressure as a scalar profile value. Mass Source Velocity Derivative (CF) For a Mass Source that is a function of velocity, sets the derivative of the mass source with respect to the x-, y-, [z-] components of velocity as a vector profile value. Mass Source Volume Fraction Derivative (for multiphase flows only) For a Mass Source that is a function of volume fraction, sets the derivative of the mass source with respect to volume fraction as a scalar profile value.

Momentum Source Option

Allows you to add additional momentum to the flow domain.


Momentum Source Option	Corresponding Value Nodes
None	None.
Specified Adds a specified momentum source to the momentum equation, see $s_{u}$ in Eqn. (665).	Momentum Source Vector profile to specify the momentum source. The dimensions of the momentum source term are force per volume. Momentum Source Pressure Derivative (CF) For a Momentum Source that is a function of pressure, sets the derivative of the momentum source with respect to pressure as a vector profile value. Momentum Source Velocity Derivative For a Momentum Source that is a function of velocity, sets the derivative of the momentum source with respect to the x-, y-, [z-] components of velocity as a vector profile value (for segregated flows) or as a tensor profile value (for coupled flows).
Fan	See Using the Fan Momentum Source.

Note	Simcenter STAR-CCM+ uses the source derivatives in the linearization of the discrete, non-linear transport equations. It is highly recommended to specify the derivatives in order to improve the stability and convergence rate of the solution.

Porous Region

Porosity: $χ$ in Eqn. (1837), the fraction of the porous medium occupied by fluid, specified as scalar profile.; Physically meaningful values are in the range $0 < χ \leq 1$ .
Porous Inertial Resistance: $P_{i}$ in Eqn. (1842), specified as tensor profile.
Porous Viscous Resistance: $P_{v}$ in Eqn. (1842), specified as tensor profile.
Tortuosity: $τ$ in Eqn. (1839), the ratio between actual (convoluted) path length between two points in the porous medium and the length of the straight path connecting the same points, specified as scalar profile.; Physically meaningful values of $τ$ are $\geq 1$ .
Porous Media Flux Option (SF): Allows you to solve without momentum fluxes. By default, the momentum equation is solved with the addition of terms for convection and viscous fluxes. See Eqn. (1843). When Discount Momentum Fluxes is On, these terms are omitted.