An Accumulator is a physics feature that allows dependent variables that are defined on domain or boundary mesh elements to be affected by particles that interact with those elements. When an
Accumulator is added directly to a physics interface, it defines a variable, called an accumulated variable, in each mesh element in a set of domains. The value of the accumulated variable in a mesh element is affected by the presence of particles within that element. Particles may either affect the accumulated variable directly, by changing the value of the accumulated variable within the mesh element occupied by the particle; or by changing the accumulated variable’s time derivative.
When an Accumulator is added as a subnode to a
Wall,
Outlet, or
Axial Symmetry node, it defines an accumulated variable on boundary elements in the selection list of its parent node, defining one degree of freedom per element. These degrees of freedom are incremented as particles hit the boundary. For more information on the
Accumulator features, see
Accumulator (Boundary) and
Accumulator (Domain).
The Accumulator features are available with all particle tracing interfaces. In addition, the following features are available in
The Charged Particle Tracing Interface to define accumulated variables for more specialized applications:
Etch,
Surface Charge Density,
Current Density, and
Heat Source.
The dedicated Multiphysics nodes and interfaces described in the section Multiphysics Couplings also use special cases of accumulators on domains to model particle-field and fluid-particle interactions.