Geometry Primitives

Geometry primitives are used for multiple purposes during the simulation setup. In this document, we will go through the types of primitives, as well as their applications.

Types of Geometry Primitives

Cartesian Box

A cartesian box is specified with the minimum and maximum box coordinates in the x, y, and z-directions. The figure below shows a cartesian box for a mesh region refinement.

Sphere

To create a sphere, one has to specify its center coordinates, as well as the radius.

Cylinder

Cylinders are often used for mesh refinements. Another common application is to create momentum sources, which mimic the effects of a fan.

To specify a cylinder, the user needs to input a point of reference for the base of the cylinder. By adjusting the axis, one can determine the direction and length of the cylinder. Finally, the user should also define the radius for the cylinder.

Point

Points are mostly used to create probe point result controls. The center coordinates are sufficient to set up a point geometry primitive.

Local Slice

Local slices are used in the pedestrian wind comfort (PWC) and incompressible (LBM) analysis types. They are planes (2D) which are placed in the domain for data visualization. For more information about local slices, please check this page.

List of Applications

Find below a list of applications where geometry primitives can be used, as well as the available types:

• Region refinement for a mesh (standard algorithm or hex-dominant algorithm): Cartesian box, sphere, and cylinder;
• Subdomains for initial conditions: Cartesian box, sphere, and cylinder;
• Momentum sources: Cartesian box, sphere, and cylinder;
• Porous media: Cartesian box and cylinder;
• Passive scalar sources: Cartesian box, sphere, and cylinder;
• Power sources: Cartesian box, sphere, and cylinder;
• Result control: Point.

Last updated: August 4th, 2020