NTC Collision Model Reference

The NTC (No Time Counter) collision model simulates droplet collisions in transient simulations. The model works in two steps, first detecting droplet collisions, then calculating the outcome of the collision.


Theory	See NTC Algorithm.
Provided By	[phase] > Models > Collision Detection
Example Node Path	[phase] > Models > NTC Collision Model
Requires	Time: Implicit Unsteady or PISO Unsteady Optional Models: Lagrangian Multiphase In the Lagrangian phase: Particle Type: Material Particles Particle Shape: Spherical Particles (selected automatically) Material: Liquid or Multi-Component Liquid Secondary Breakup: any
Activates	Model Controls	Collision Dynamics See Collision Dynamics Properties.
	Materials	Surface Tension for Liquid under the Lagrangian phase.
	Field Functions	Collision Efficiency, Collision Outcome, Droplet Surface Tension, Relative Weber Number. See Lagrangian Multiphase Field Function Reference.

Collision Dynamics Properties

The Collision Dynamics node controls the selection and customizing of the collision outcome algorithm.


Method	Corresponding Method Node
Ashgriz Method Selects a collision outcome map with the following outcomes: grazing (stretching) separation, coalescence, and reflexive separation.	Ashgriz Method Exposes sub-nodes for each collision outcome: Grazing Separation Criteria This node exposes the following empirical constants from Eqn. (3147): Exponent $a$ PreExponent $A$ WeOffset ${W e}_{c}$ Reflexive Separation Criteria This node exposes the following empirical constants from Eqn. (3147): Exponent $a$ PreExponent $A$ WeOffset ${W e}_{c}$ Collision Gamma Function This node exposes the following empirical constants from Eqn. (3148): FGamma_3 $α_{3}$ FGamma_2 $α_{2}$ FGamma_1 $α_{1}$ FGamma_0 $α_{0}$
Composite Method Selects a collision outcome map with the following outcomes: grazing (stretching) separation, bouncing, coalescence, and reflexive separation.	Composite Method Exposes sub-nodes for the methods for boundary curves: Bounce Method None Excludes the bounce mode from consideration in the composite method. Sommerfeld Selects the Sommerfeld method for the bounce composite method. This node exposes the following empirical constants from Eqn. (3155) : K0 $k_{0}$ , K1 $k_{1}$ , K2 $k_{2}$ , K3 $k_{3}$ , KL $k_{l}$ P0 $Φ_{0}$ , P1 $Φ_{1}$ , P2 $Φ_{2}$ , P3 $Φ_{3}$ , PL $Φ_{l}$ B0 $β_{0}$ , B1 $β_{1}$ , B2 $β_{2}$ , B3 $β_{3}$ , BL $β_{l}$ Stretching Separation Method None Excludes the stretching separation mode from consideration in the composite method. Suo-Jia Selects the Suo-Jia method for the stretching separation composite method. This node exposes the following empirical constants from Eqn. (3157) : A0 $a_{0}$ A1 $a_{1}$ A2 $a_{2}$ Reflexive Separation Method None Excludes the reflexive separation mode from consideration in the composite method. Ashgriz Selects the Ashgriz method for the reflexive separation composite method.
ORourke Method Selects a collision outcome map with the following outcomes: grazing (stretching) separation, coalescence, and bouncing.	ORourke Method Exposes sub-nodes for each collision outcome: Coalescence Criteria This node exposes the following empirical constants from Eqn. (3147): Exponent $a$ PreExponent $A$ WeOffset ${W e}_{c}$ Bouncing Criteria This node exposes the following empirical constants from Eqn. (3147): Exponent $a$ PreExponent $A$ WeOffset ${W e}_{c}$ Collision Gamma Function This node exposes the following empirical constants from Eqn. (3148): FGamma_3 $α_{3}$ FGamma_2 $α_{2}$ FGamma_1 $α_{1}$ FGamma_0 $α_{0}$