Force
The Force node is only available when Newtonian or Newtonian, first order is selected as the Formulation in the physics interface Particle Release and Propagation section.
Use the Force node to exert user-defined forces on particles to influence their motion. All forces defined in the model are added together to compute the total force on the particles. The force can be specified directly or using a susceptibility and field.
Force
Select an option from the Specify force list: Directly (the default) or Using susceptibility and field. For Directly enter values or expressions for the Force F (SI unit: N) based on space dimension.
For Using susceptibility and field:
•
Select Isotropic, Diagonal, Symmetric, or Full and enter a value or expression in the field or matrix (based on space dimension) for the Susceptibility χ.
•
Enter values or expressions for the Field Γ.
The units of the susceptibility and field are controlled by the Units section.
Affected Particles
Select an option from the Particles to affect list: All (the default), Single species, or Logical expression.
•
If All is selected, the force is applied to every particle in the selected domains.
•
For Single species select an option from the Affected particle properties list. At least one Particle Properties node is always available, because it is a default feature. If other instances of the Particle Properties feature have been added to the model, then they can be selected from the list. Use this option to apply a force to a specific type or species of particle.
•
For Logical expression enter a Logical expression for inclusion e. The default is 1. The force is applied to all particles in the selected domains for which the logical expression is nonzero.
Units
This section is available if Using susceptibility and field is selected from the Specify force list. Select a Susceptibility quantity from the list; the default is Dimensionless [1]. To enter a unit, select None from the list and in the Unit field enter a value, for example, K, m/s, or mol/m^3. The unit of the Susceptibility is changed to the specified unit. The unit of the Field is changed so that the product of the susceptibility and field has a unit of force.