Flow Boundary Condition dialog box – Opening options

Name
Name	Sets a name for the simulation object.Description opens an editor that lets you type a description for the boundary condition.
Destination Folder
Simulation Object Container	Specifies the folder in the Simulation Navigator in which the boundary condition will be stored. The list includes the root container and existing folders that you created using the New Folder command. Examples of a root container include Load Container, Constraint Container, and Simulation Object Container.
Folder Manager	Displays a hierarchical listing of existing folders. To create a new folder, right-click any level of the hierarchy and choose New Folder.
Opening Region
Group Reference	Applies the boundary condition to the selected group.For more information, see Group Reference options.
Select Object	Lets you select the faces or elements to specify the boundary of the flow domain.Excluded lets you remove individual entities from within your selected object.
Stacked Smart Selector Methods	Opens the Smart Selector Methods dialog box where you can specify a progression of smart selection filters.For more information, see Smart Selector Methods dialog box.
External Conditions
External Conditions	Specifies the temperature, humidity, and turbulence characteristics at the boundary.AmbientSpecifies ambient flow conditions at the boundary, which you define on the Ambient Conditions page of the Solution dialog box.External Conditions modeling objectSpecifies the flow conditions at the boundary through the selected External Conditions modeling object.You can also select a previously defined External Conditions modeling object from the list or click Create Modeling Object to define a new modeling object.Click Edit to modify the specified modeling object.
Turbulence Characteristics	Specifies which method is used to specify turbulence properties of fluid based on available data derived from experiment or standard references.AutomaticLets the solver compute automatically turbulence characteristics.Turbulence Characteristics modeling objectSpecifies the method for calculation initial turbulence quantities through the selected Turbulence Characteristics modeling object.You can also select a previously defined Turbulence Characteristics modeling object from the list or click Create Modeling Object to define a new modeling object.Click Edit to modify the specified modeling object.For more information, see Turbulence Characteristics.
External Pressure Type	Specifies whether the pressure at the opening is absolute or relative to ambient pressure.
External Absolute Pressure	Appears when External Pressure Type is set to Absolute.Specifies the absolute pressure at the opening.AmbientDefines the external absolute pressure to the value that you set on the Ambient Conditions page of the Solution dialog box.SpecifyDefines a constant external absolute pressure or a time-varying external absolute pressure. You set the value in the Pressure Value box.
External Relative Pressure	Appears when External Pressure Type is set to Relative. Specifies a constant relative pressure or a time-varying relative pressure at the opening. You define the magnitude with a constant value in the External Relative Pressure box. For more information, see Additional magnitude options.
Head Loss
Head Loss	Lets you define a pressure drop across the opening due to a planar device, such as a screen or filter. Choose a previously defined Planar Head Loss modeling object from the list or click Create Modeling Object to create a new one. See Planar Head Loss.
Tracer Fluid
Available if you choose an External Conditions modeling object from the External Conditions list.
Tracer Fluid	Defines the mixing of one or more tracer fluids entering the fluid domain through the inlet.None specifies that no mixing occurs.Specify Fractions lets you specify a Tracer Fluid modeling object and a matching mass fraction. See Tracer Fluid for more information.
Tracer Fluid List	Opens the Modeling Objects Manager where you can select or create a Tracer Fluid modeling object.See Model a tracer fluid for more information.
Tracer Fluid Mass Fractions	Sets the mass fractions for the Tracer Fluid modeling objects you select in the Tracer Fluid List.As a good practice, enter values from 0 to 1 for each mass fraction. The percentage of air is calculated as 1–∑Mass Fractions.If the sum of the mass fractions you enter is greater than 1, the values are normalized.You can use Cut , Copy , and Paste commands.
Mixture
Available if you choose an External Conditions modeling object from the External Conditions list.
Mixture	Specifies the mass fractions for the components of a mixture for the ambient fluid domain.NoneIndicates that there is no mixture entering the fluid domain.Homogeneous Gas MixtureSets the mass fractions for the homogenous mixture components.Immiscible Fluid MixtureSets the area fraction of the tracked fluid in the immiscible mixture entering the fluid enclosure. The area fraction value must be between 0 and 1, and it can vary with time in a transient analysis. If it is not defined, the flow solver assigns a value of 1. You define the value in the Tracked Fluid Area Fraction box.
Mixture Mass Fractions	Appears when Mixture is set to Homogeneous Gas MixtureSets the mass fractions for the homogenous mixture components.As a good practice, enter values from 0 to 1 for each mass fraction. If the sum of the mass fractions you enter is greater than 1, the values are normalized.You can use Cut , Copy , and Paste commands.
Flow Direction
Alignment	Specifies the general direction of the fluid flow, only when the Opening type acts as an inlet.With the Opening type, local fluid dynamics determine the general flow direction during the solution. You can still model devices such as louvers by selecting a vector to represent the angle of deflection. This vector does not, however, determine whether the Opening acts as an inlet or an outlet.

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Flow Boundary Condition dialog box – Opening options, Simcenter 3D 2021.1 Series

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