In the Electrostatic Effects subtab, the electric field term in the governing equation can be switched on. Electrostatic Effects cannot be applied when porous materials are present in the structure. If Include Electrostatic Effects is checked, electrostatic effects between solids and particles in the fluid are considered. If the button is unchecked the electrostatic forces are set to .

For the Particle Charge the following options are available:

• No Charge
• Select Proportional to surface area to define a Surface Charge Density/ (C/m2). The charge on a particle is obtained by multiplying this value with the particle surface area.
  
• Choose Individual per particle type to define the charge of each particle type separately into the table on the Particles Size Distribution subtab. Enter the individual values in the Size Distribution subtab as shown here.
• Select Boltzmann Random to randomly distribute particle charges according to a normal (or Gaussian) distribution with a mean value of and a standard deviation of . Here, denotes the particle diameter, the dielectric constant, the Boltzmann constant, the temperature, and the charge of an electron. This option can be used to, e.g., model the particle charge of dust in air, that follows a Boltzmann distribution.

For Material Charge two options are available:

• Choose Constant surface charge density to define one Surface Charge Density / (C/m2). This surface charge density is multiplied with the material surface area to get the charge of each material.
  
• Select Individual per material type to define the surface charge for each solid material separately. The surfaces charges for each material are set in the Interaction Model subtab.
  

Check Enable Dielectrophoresis to simulate polarizable particles that are suspended in a non-uniform electric field. The electric field polarizes the particle, even if it is not charged, and the polarized particle experiences a force along the field lines of the gradient of the electrical field.

Enter the Relative Permittivity of the fluid medium and the particles. Permittivity is a materials property that affects the Coulomb force between two charged sites in the material. Relative Permittivity is the factor by which the electric field between the charges is reduced relative to vacuum.