Free Molecular Heating dialog box (SST)

Type
Illuminate All ElementsDetermines which elements are illuminated for the free molecular heating, automatically.Illuminate Selected ElementsLimits the thermal solver’s search for illuminated elements to only the elements that you select.This option can save calculation time when some parts of the model obviously have no direct view of the source.
Name
Name	Sets the simulation object name. The name appears in the Simulation Navigator.Description opens a text editor to let you type a description for the simulation object.
Destination Folder
Simulation Object Container	Specifies the folder in the Simulation Navigator in which the boundary condition is 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.
Illuminated Region
Appears when Type is set to Illuminate All Elements.
Select Object	Selects the complete model automatically.
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.
Top Side Illuminated Region / Bottom Side Illuminated Region
Appears when Type is set to Illuminate Selected Elements.
Group Reference	Applies the simulation object to the selected group. For more information, see Group Reference options.
Select Object	Lets you select elements or polygon faces that are impacted by the free molecules.Excluded lets you remove elements from within your selected object. The software does not apply the boundary condition to excluded elements.Note: The Element Selection Filtering options are available when the Type Filter list on the Top Border bar is set to Elements.
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.
Parameters
Accommodation Coefficient	Sets the accommodation coefficient, α, that is used to compute the heat flux generated by the free low density gas molecules impacting the spacecraft surface. The value of α needs to be between 0 and 1.
Heat Flux Method	Specifies the heat flux computation method.Heat FluxDefines a constant or time-varying heat flux. Specify the value in the Heat Flux box.Velocity and DensityDefines a constant or time-varying velocity for the spacecraft and a constant or time-varying atmospheric density. Specify the velocity value in the Velocity box and the density value in the Density box.DensityDefines a constant, time-varying, or altitude-varying atmospheric density. Specify the value in the Density box. For more information, see Additional magnitude options.Note: For the Density heat flux computation method, because the software computes the velocity and density from the spacecraft’s orbital velocity and altitude, you must have an Orbit modeling object defined in your model.The software computes the requested free molecular flux result sets only at the times you specify in the table field or calculation positions that you define for the orbit. The time data that you specify here overrides the results sampling settings you specify on the Transient Setup page in the Solution dialog box.
Heat Flux Direction	Specifies the direction of the free molecular heat flux.Along VectorLets you specify the vector that represents the direction of the heat flux due to free molecular heating.This option is available when Heat Flux Method is set to Heat Flux or Velocity and Density.FieldLets you specify a table that defines the direction of the heat flux due to free molecular heating at specified times. You can specify the table using either Cartesian coordinate system or spherical coordinate system.This option is available when Heat Flux Method is set to Heat Flux or Velocity and Density.From OrbitDetermines the direction of the heat flux due to free molecular heating from the path that the spacecraft follows in the orbit. The direction opposes the velocity vector.This option is available when Heat Flux Method is set to Density or Altitude Dependent Density.
Specify Vector	Appears when the Heat Flux Direction is set to Along Vector.Lets you specify the direction of the free molecular heat flux. See Vector dialog box for more information.
Monte Carlo Settings	Sets the Monte Carlo Settings modeling object for computing free molecular fluxes.Select a Monte Carlo Settings modeling object from the list or click Create Modeling Object to create a new modeling object.Note: You must clear the Calculate View Factors only check box in the Monte Carlo Settings dialog box.

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Free Molecular Heating dialog box (SST), Simcenter 3D 2021.1 Series

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