Command reference help topics > Flow Boundary Condition dialog box (Flow/ESC/Multiphysics)
Flow Boundary Condition dialog box – Outlet Flow 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. |
| 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. |
| Magnitude | |
| Mode | Controls how you define the flow conditions at the fan.VelocityLets you specify the flow velocity at the inlet. The flow velocity is the speed of the fluid movement normal to the boundary condition surface. You define the magnitude with a constant value in the Velocity box. When the flow is deflected using the Alignment Along Vector option or the Swirl option, the volumetric flow rate is preserved.Velocity VectorLets you specify the flow velocity vector components at the inlet. The components can either be constant, or vary with respect to time and spatial variables. You can use a formula field, a table of fields, or a 4D field to define how the flow velocity vector components vary with respect to time and spatial variables.To define constant velocity vector components, set the Velocity list to Expressions. You define the flow velocity vector components in the Vx, Vy, and Vz boxes using an expression. To define the velocity vector components using tabular data, set the Velocity list to Fields. You can define a formula field, a table of fields, or a 4D field. You can also define the Scale Factors for the flow velocity vector components in the Vx, Vy, and Vz boxes.Mass FlowLets you specify the mass flow per unit of time through the inlet. You define the magnitude with a constant value in the Mass Flow box.Volume FlowLets you specify the volume flow per unit of time through the inlet. You define the magnitude with a constant value in the Volume Flow box.Pressure RiseLets you specify the change in pressure across the inlet. You define the magnitude with a constant value in the Pressure Rise box. The pressure that you specify is a total pressure, relative to ambient pressure. Total pressure is the static pressure plus the dynamic pressure.Fan CurveLets you use a fan curve definition to specify the relationship between flow rate and static pressure rise across the inlet in the Fan Curve box. In Simcenter 3D Electronic Systems Cooling, you can select a pre-defined fan curve from the manufacturing data when you click Fan Catalog . With each of these options, if you use a field definition to define flow conditions and the time is outside of the defined field values, the software uses the last value defined by the field until the specified End Time of the analysis. The end time is specified on the Transient Setup page of the Solution dialog box.For more information, see Additional magnitude options. |
| Head Loss | |
| Head Loss | Appears only when Pressure Rise or Fan Curves is selected from the Mode list.Lets you define a pressure drop across the inlet 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. |
| Fan Control | |
| Controller Type | Specifies how the speed of the Flow Boundary Condition is controlled.None specifies that the speed at the boundary condition is not controlled.Thermostat lets you control the speed with a Thermostat modeling object. Choose a previously defined Thermostat modeling object from the list or click Create Modeling Object to create a new one. See Thermostat for more information.Speed Control lets you control the speed based on the temperature of a sensor. Choose a previously defined Fan Speed Controller modeling object from the list or click Create Modeling Object to create a new one. See Fan Speed Controller for more information. |
| Nominal Fan Speed | If you chose Velocity, Mass Flow, or Volume Flow from the Mode list, the Nominal Fan Speed value corresponds to the specified velocity or flow value (Qnominal). The software obtains the flow rate at a new temperature during the solve using this equation:Qnew = Qnominal × RPMnew / RPMnominalIf you chose Pressure Rise from the Mode list, the Nominal Fan Speed value corresponds to the specified pressure rise value (dPnominal). The software obtains the flow rate at a new temperature during the solve this equation: dPnew = dPnominal × (RPMnew / RPMnominal)2 If you chose Fan Curve from the Mode list, the software uses the two equations above to compute the fan operating point. |
How do I
Create a Flow Boundary Condition
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Flow Boundary Condition
Flow Boundary Condition types
Working with fan curves
Modeling heat loss or gain in a recirculation loop
Modeling fan swirl
Flow boundary condition modeling
External Conditions
Planar Head Loss
Look up more details
Flow Boundary Condition dialog box – Inlet Flow options
Flow Boundary Condition dialog box – Opening options
Flow Boundary Condition dialog box– Internal Fan options
Flow Boundary Condition dialog box – Recirculation Loop options
Flow Boundary Condition dialog box– Convective Outflow options
Flow Boundary Condition dialog box– Static Pressure options
Flow Boundary Condition dialog box– Bursting Membrane options
Flow Boundary Condition dialog box– Flap options
Defining the mesh size for fluid modeling
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Flow Boundary Condition dialog box – Outlet Flow options, Simcenter 3D 2021.1 Series
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Source: https://docs.sw.siemens.com/en-US/doc/289054037/PL20200601120302950.advanced/id631656 · retrieved 2026-07-17