Velocity Reinitialization
The Velocity Reinitialization node is only available when Newtonian, Newtonian, first order, Lagrangian, or Hamiltonian is selected as the Formulation in the physics interface Particle Release and Propagation section.
Use the Velocity Reinitialization node to reset the particle velocity to an arbitrary expression if a specific condition is satisfied.
The Secondary Emission and Accumulator (for Velocity Reinitialization) subnodes are available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.
Velocity Reinitialization
Enter an expression for the Velocity reinitialization condition e (dimensionless). If this expression is nonzero then the effect of the Velocity Reinitialization node is applied to the particle. This expression is evaluated at every time step taken by the solver.
Select the Specify reinitialization time check box to make the velocity reinitialization occur at a specific time. If this check box is selected, enter a value or expression for the Reinitialization time tr (SI unit: s). The default value is 0.
If the Specify reinitialization time check box is cleared, the reinitialization condition is only evaluated at the beginning of each time step taken by the solver, so each particle’s velocity can only be reinitialized once per time step.
If the Specify reinitialization time check box is selected, the reinitialization condition and time are reevaluated after every velocity reinitialization and wall interaction, so it is possible for each particle’s velocity to be reinitialized multiple times in a single time step taken by the solver.
Select an option from the Effect on primary particle list: None, Reinitialize (the default), Freeze, Stick, or Disappear. If None is selected, the trajectory of the primary particle is not affected, although it is still possible to release secondary particles at the primary particle’s position and to reinitialize its auxiliary dependent variables.
For Reinitialize the velocity is reinitialized at each time step according to the expression specified in the Reinitialized particle velocity vr (SI unit: m/s) field. Both the Velocity reinitialization condition and the Reinitialized particle velocity can be functions of any of the particle variables, that is, particle position, energy, and so forth.
The options Freeze, Stick, and Disappear are identical to the same options described for the Wall node.
New Value of Auxiliary Dependent Variables
This section is available if an Auxiliary Dependent Variable has been added to the model. The values of auxiliary variables can be changed whenever the Velocity reinitialization condition is satisfied. See Wall for all settings.