Fluid Screen¶
Introduction¶
Fluid screens are used to restrict flow across a two-dimensional surface based on a pressure difference across the screen itself. This object can be used to model filters, perforated plates, screens, mesh, etc. The fluid screen is represented as 2D plane with a UDF defining the local velocity through the screen as a function of the local pressure drop across the screen. Importantly, the pressure drop and flow rate along the screen surface are considered on a voxel-by-voxel basis. As such, spatial variations in the flow field entering the screen will manifest in the flow exiting the screen.
Fluid screens are modeled as planes with a position/orientation defined using a point and vector. The point defines the location of the screen, and the vector describes the orientation. Note that the screen vector must be grid-aligned, meaning the plane will be aligned one of the basis X, Y, and Z unit vectors.
The UDF for the local fluid velocity across the screen can be an arbitrary function of the local fluid pressure drop. These functions may be empirically derived or patterned after more fundamental relationships, such as the Darcy-Weisbach and/or Ergun equations.
Fluid screens are like recirculation returns and porous media, but there are some important differences. Unlike recirculation returns, which impose a uniform velocity across the recirculation loop, the flow field leaving the screen will be informed by spatial variations in the velocity profiles along the screen intake surface. Recirculation returns, however, can be attached to any intake/return pairing without regard to location, orientation, or aspect ratio. Porous media are used to implicitly model packed structures and predict the effects of this packed structure on flow. Unlike fluid screens, where the relationship between pressure drop and fluid flow are defined directly, porous media are characterized by the packing structure (e.g., porosity, permeability, and structure function). The relationship between pressure drop and flow are then calculated at runtime from these user-defined properties of the packed bed.
Property Grid¶
General¶
- Position
This point defines the location of the screen.
- Screen Orientation
The orientation of the screen. Note that the screen vector must be grid-aligned, meaning the plane will be aligned one of the basis X, Y, and Z unit vectors.
- X
Aligns screen in the x-direction.
- Y
Aligns screen in the y-direction.
- Z
Aligns screen in the z-direction.
- Local Screen Velocity UDF
m/s | This UDF defines the velocity along a screen surface. One output must be defined within the UDF: a floating point variable named
v. This velocity can be a function of the local fluid properties and the local pressure drop,dP, which is calculated for each voxel along the screen in the direction of the Screen Orientation. This is a local UDF, calculated on a voxel-by-voxel basis using the local fluid properties. The UDF is only applied only to cells adjacent to the screen plane.Download Sample File:
Local Screen Velocity
Display Attributes¶
- Visible
The ability to show or hide the object.
- Shown
The object is shown in the 3D view.
- Hidden
The object is hidden in the 3D view.
- Mode
This offers two options to view the object.
- Wire
The object is shown as a wire frame.
- Width
The width of the line used to render the object in the 3D view.
- Shaded
The object is shown as a shaded surface.
- Material
This allows the user to change the material of the object with the following options:
Aluminum
Steel
Chrome
Plastic
- Glass
This selection also offers opacity.
- Opacity
This scale allows the user to change the opacity of the object.
- Color
This offers to change the color of the object.
Fluid Screen Toolbar¶
Context-Specific Toolbar Forms |
Description |
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The Help command launches the M-Star reference documentation in your web browser. |
HelpFor a full description of each option, see Context-Specific Toolbar selections.