Create SPH Mesh

Use the SPH tool to define 0D Smooth Particle Hydrodynamics (SPH) mesh.

1. From the 1D ribbon, click the SPH tool.

   
   
   Figure 1.

2. Define the mesh.

   Option	Action
   Entities	Select the entities that define the volume to be filled with SPH elements.
   Use reference	SPH elements are generated at the corners/face centers of the cubes which fall within the user defined criteria. Select the Use reference check box to specify which point the generation of cubes should be started. The base point defines the starting point for cube generation, and is utilized by the mesher as a starting point.
   Origin type	Global Uses (0, 0, 0) for the reference point. Local Define node coordinates for the reference point. Restriction: Only available when the Use reference check box is selected.
   Mesh orientation	Choose a method for defining the orientation of SPH elements. Global Use the default global system to align generated SPH elements. Local Define reference systems local to the model orientation. Generated SPH elements are aligned using the user defined local system.
   Pitch	Enter the pitch. Note: Smaller numbers will result in more elements within the same space, but this will not affect the mass or density of the substance (gas, fluid, and so on) that the particles represent.
   Method (Pitch)	Choose a method for specifying the distances between each SPH particle. Simple cubic Arrange SPH particles in groups of 8, each particle being a corner of a cube. Face centered cubic Arrange the particles in groups of 14, forming the corners and the center of each face of a cube. This is similar to a hexagonal close packed (HCP) structure and is recommended for use in Radioss models.
   Mass definition	Enter the mass definition.
   Method (Mass definition)	Choose a method for specifying the quantity of fluid. Material density Specify its density (the total mass is then determined by the volume filled). Filled volume mass Specify its total mass (volume and density is determined by the model volume filled).
   Volume definition	Choose which elements to generate SPH elements for. All Generate SPH elements in all of the volumes in the model. Enclosed Generate SPH elements in the volumes enclosed by the defined nodes, and ignores the remaining volumes. Nth largest Specify which volumes to generate SPH elements in by defining the wrap size index in terms of volume size. Specify the largest volume by entering 1; specify the second largest volume by entering 2. Exclude enclosed Ignore the volume(s) enclosed by the defined nodes and generate SPH elements in the remaining volumes.
   Partial fill	Model a fluid or gas that does not completely fill the selected volume. Figure 2.
   Value	Specify a percentage/depth of the volume to fill. Calculation of the volume is based on the lowest point of the model, parallel to the user defined plane. Restriction: Only available when the Partial fill check box is selected.
   Method (Partial fill)	Choose a method Percent Percentage of the volume to fill. Depth Depth of the volume to fill. Restriction: Only available when the Partial fill check box is selected.
   Direction	Define the direction of fill, which is generally the opposite of the direction of gravity when the filled volume is installed in the real world. Restriction: Only available when the Partial fill check box is selected.
   Reverse direction	If the particle mass is filled along the correct axis, but in the wrong direction (for example from the top of a fuel tank downward) select Reverse direction to fix this. Restriction: Only available when the Partial fill check box is selected.
   Wall offset	Create SPH particles offset from a wall up to a distance you specify. The thickness of SPH elements is created from input. The distance between the SPH particles is driven by the pitch.
   External to volume	Create SPH particles outside of the defined volume. Restriction: Only available when the Wall Offset check box is selected, which enables the capability to offset SPH elements from selected volume surfaces.
   Wall clearance	Create SPH particles from the specified distance. Tip: This is useful when trying to avoid contact of SPH elements with walls at the beginning of the solver run (first iteration) and want the solver to run smoothly.

3. Click Mesh.