Particle Remediation Model Reference

The Particle Remediation model regulates particle behavior to ensure accurate and efficient flow representation within the SPH multiphase computational domain.

You define the parameters to remedy the fluid particles leaving the region of interest of the computational model. The model then ensures that these particles are removed from the simulation according to certain user-specified criteria to optimize computational resources. Particle disordering (shifting) method enables a near uniform particle distribution in the domain.

表 1. Particle Remediation Model Reference
Theory	See 颗粒修复.
Provided By	[physics continuum] > Models > Multiphase Model > Optional Models
Example Node Path	Continua > Physics 1 > Models > Particle Remediation
Requires	Pre-requisite selections: Material: Multiphase Multiphase Model: Smoothed-Particle Hydrodynamics (SPH) Optional Models: Particle Remediation
Properties	Key properties are: Enable Position-Based Removal, Enable Velocity-Based Removal, Velocity-Based Criterion, Shifting Option, Shifting Coefficient, and Shifting Limit
Activates	Model Controls (Nodes)	Position-Based Criterion See Particle Remediation Controls.
	Report Options	Position-Based Removed Particles Velocity-Based Removed Particles See Particle Remediation Reports.
	Field Functions	None.

Particle Remediation Properties

Enable Position-Based Removal: When activated, provides the Position-Based Criterion node which allows for removing particles that cross a Bounded Shape geometry part surface. The selected part (bounding box) is stationary, that is, it remains unaffected by the motion of parts. The particles are removed from the simulation based on their positions with respect to the bounded shape. You use this option to remove particles that escape the simulation in unbounded geometry cases or leak through boundaries in bounded geometry cases.

Enable Velocity-Based Removal: When activated, provides the Velocity-Based Criterion property which allows for removing particles when they exceed a specified maximum velocity threshold. You use this option to remove particles that have unphysical velocities, due to local instabilities or particles that are trapped between boundaries.

Velocity-Based Criterion: Specifies the maximum velocity that particles can reach. Particles with velocities above this value are removed from the simulation.

Shifting Option

Selects the particle shifting method. This method redistributes the fluid particles in order to ensure a homogeneous particle distribution.

Method	Corresponding Properties
None Shifting is not accounted for.	None.
Skillen Activates the Skillen shifting method.	Shifting Coefficient Specifies $χ$ in Eqn. (1126). A value of 0 corresponds to no shifting applied. You are advised to specify a value of 1 if you want to apply shifting. Shifting Limit Specifies $ξ$ Eqn. (1128). You are advised to specify a value of 0.1, which means that the maximum correction applied to the velocity is 0.1 times the amplitude of the current velocity.

Method

Corresponding Properties

None: Shifting is not accounted for.

None.

Skillen: Activates the Skillen shifting method.

Shifting Coefficient: Specifies $χ$ in Eqn. (1126).; A value of 0 corresponds to no shifting applied. You are advised to specify a value of 1 if you want to apply shifting.

Shifting Limit: Specifies $ξ$ Eqn. (1128).
You are advised to specify a value of 0.1, which means that the maximum correction applied to the velocity is 0.1 times the amplitude of the current velocity.

Particle Remediation Controls

Position-Based Criterion

Allows you to use a Bounded Shape geometry part for the position-based particle removal method.

Parts: Selects the Bounded Shape geometry part which establishes the criterion for position-based particle removal. Particles that cross the surface of this part are automatically removed during the simulation.