Flow Surface Parameters dialog box (Multiphysics)

Modeling Object
Name	Sets the name for the modeling object.
Label	Sets a unique numeric identifier for the modeling object.
Properties
Description	Lets you enter a description for the modeling object.
Parameters
Non-fluid 2D and 3D Elements Block Flow	Detects all polygon faces and bodies meshed with elements having non-fluid material properties. Where these polygon faces and bodies contact the fluid mesh, the solver models friction and convection using the options specified in the Parameters group. With this option if non-fluid 2D or 3D elements are embedded in the fluid mesh, they block the flow.If you clear this option, the flow solver does not calculate friction and convection on polygon faces and bodies meshed with elements having non-fluid properties in contact with the fluid unless you create a Flow Surface simulation object on them, or unless they are part of a Solid type of a Flow Blockage simulation object. With this option if non-fluid 2D or 3D elements are embedded in the fluid mesh, they do not block the flow.
Wall Treatment	Appears when Non-fluid 2D and 3D Elements Block Flow is selected.Specifies how the flow solver models the near-wall region of a flow surface.No Slip WallResolves the flow field in the near-wall region, including the viscous sublayer. Your model requires a finer mesh near the wall.Slip WallEliminates any surface drag calculations for the surface of the blockage and assigns automatic convection properties.Wall FunctionProvides near-wall boundary conditions for the momentum and turbulence transport equations without resolving the viscous sublayer. Applicable only when you also select one of the following turbulence models: K-Omega, SST — Shear Stress Transport, or LES — Large Eddy Simulation(Solution dialog box→Solution Details page→Flow Control group→Turbulence Model list)Note: The implementations of the Standard K-Epsilon, RNG K-Epsilon, Realizable K-Epsilon, and Mixing Length turbulence models always use wall functions.Hybrid Wall FunctionUses enhanced wall functions that are less sensitive to the first layer y+ values and provides a more robust performance upstream of the separation point in comparison with standard wall functions. Hybrid wall functions transition smoothly between wall-resolved (no slip) and wall function corrected treatments based on local grid quality.Applicable only when you also select one of the following turbulence models: K-Omega or SST — Shear Stress Transport.Note: A single solution can only contain one type of wall functions: you cannot specify standard wall functions on some surfaces and hybrid wall functions on others. A combination of flow surfaces with and without wall functions is allowed.For more information see Meshing for turbulence modeling.
Default Wall Friction	Available when Wall Treatment is set to anything except Slip Wall.Specifies how the software computes wall friction. Smooth – With FrictionApplies the drag on a smooth wall. The flow solver computes the drag force by integrating the shear stress over the wall surface.Rough Applies drag on a rough wall. The roughness effect is included in computation using the Sand Grain Roughness Height value that you specify. Surface roughness tends to increase convection heat transfer by introducing flow turbulence.Note: The specified Sand Grain Roughness Height value must not exceed the size of the fluid elements next to the surface.
Default Convection Properties	Specifies the default convection properties the solver uses for surfaces in contact with the fluid mesh.AutomaticCalculates default convection properties.Convection PropertiesDefines the convection properties in the Convection Properties modeling object. You can select a previously defined one from the list or select to create a new one.
Reference Temperature for Bulk Heat Transfer Coefficient	Specifies the temperature the solver uses to calculate the bulk heat transfer coefficient.AmbientUses the Fluid Temperature specified on the Ambient Conditions page in the Solution dialog box. If the ambient fluid temperature is defined as time varying, then the software uses the interpolated value at the time step.LocalApplies the nearest calculated node temperature for each convecting element.SpecifyApplies the temperature you enter in the Reference Temperature box.
Default Particle Impact Type	Specifies whether the particles stick to the wall or rebound. This setting applies to all flow surfaces unless you modify it for a specific surface using the Flow Surface simulation object.ReboundIndicates that the particles rebound on the walls of the fluid domain. The flow solver needs a value for the coefficient of restitution, α, to compute how much energy the particle loses when it hits the wall. You set the value in the Default Coefficient of Restitution box. The specified value must be: 0 ≤ α ≤ 1.StickIndicates that the particles stick to the walls.

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Flow Surface Parameters dialog box (Multiphysics), Simcenter 3D 2021.1 Series

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