Accumulator (Boundary)

The subnode is available from the context menu (right-click the Wall, Outlet, Periodic Condition or Axial Symmetry parent node) or from the toolbar, menu. Each subnode defines a variable, called the accumulated variable, on each boundary element in the selection of the parent node. Whenever a particle hits a boundary element, the value of the accumulated variable in that element is incremented based on the value of the user-defined term R for the incident particle.

Select an option from the list: (default) or .

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For the accumulated variable is divided by the surface area (in 3D) or length (in 2D) of the boundary element where it is defined.

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For the accumulated variable is the sum of the source terms of all particles that hit the boundary element, and is unaffected by the boundary element size.

Select an option from the list: (default) or .

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For the accumulated variable is affected by all particles that hit the boundary element, including those that pass through or are reflected by the boundary.

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For the accumulated variable is only affected by particles that freeze or stick to the boundary element.

Enter the . The default is rpb. The accumulated variable is defined as <scope>.<name>, where <scope> includes the name of the physics interface node, parent boundary condition, and the node; and <name> is the accumulated variable name.

For example, if the subnode is added to a Wall node in an instance of the Mathematical Particle Tracing interface using the default variable name rpb, the accumulated variable name might be pt.wall1.bacc1.rpb.

Enter a R. The unit of the source term depends on the settings in the section. Whenever a particle collides with a boundary element in the selection of the parent node, the accumulated variable in that element is incremented by the source term. If the is set to , the source term is divided by the area of the boundary element (in 3D) or the length of the boundary element (in 2D).

Select a from the list; the default is . To enter a unit, select from the list and in the field enter a value, for example, K, m/s, or mol/m^3.

The accumulated variables are computed using discontinuous shape functions. Select the check box to compute a smoothed accumulated variable by computing the average value of the variable within a sphere of a user-defined radius. Then enter a r (SI unit: m). The default is 0.1 m.