surface model superquadric

Purpose

Modelling surface of superquadric particles.

Syntax

surface superquadric [other model_type/model_name pairs as described here ] settings keyword values

zero or one keyword/value pair may be appended after the keyword settings (after all models are specified)

curvatureLimitFactor values = more or equal 0
gaussianCurvature values = yes or no
meanCurvature values = yes or no

Description

This is the surface model for smooth convex superquadric particles. For contact detection and force calculation algorithms see Podlozhnyuk et al.. Calculation of particle radii $R_1$ and $R_2$ in Hertz or Hooke models is based on mean or gaussian curvature radius at a contact point. The effective radius $R^*$ is limited by the factor of curvatureLimitFactor with respect to $R^*$ calculated using $R_1$ and $R_2$ as volume equivalent radii. If curvatureLimitFactor=0 particle radii $R_1$ and $R_2$ are volume equivalent radii that don’t depend on the contact point.

This model is used in the framework of superquadric simulations. For more information see also the SUPERQUADRIC guide. In case of superquadric-sphere interaction, please use instead surface model sphere/superquadric.

Restrictions

Requires particle_shape superquadric.

meanCurvature and gaussianCurvature cannot be simultaneously yes

Coarse-graining information:

Using coarsegraining in combination with this command might lead to statistically different dynamics and system state. To the best knowledge of the developers, the cross-influence between this command and coarse-graining is unknown.

Default

curvatureLimitFactor = 0 gaussianCurvature = ‘no’ meanCurvature = ‘no’

Literature

[1] Podlozhnyuk, A., Pirker, S., & Kloss, C. (2017). Efficient implementation of superquadric particles in Discrete Element Method within an open-source framework. Computational Particle Mechanics, 4(1), 101-118.