rolling_friction model simplistic

Purpose

Extremely simplistic rolling friction model, only for reference (see below).

Syntax

rolling_friction simplistic [other model_type/model_name pairs as described here ]

Associated material properties

Material interaction properties

coefficientRollingFriction ( $\mu_r$ ): Coefficient of rolling friction [–]

Description

This model can be used in the rolling_friction argument of both particle_contact_model and wall_contact_model.

The simplistic rolling friction model adds the following torque contribution $M_r$ [Nm] to the angular momentum equation:

$M_{r} = \mu_r \|F_n\| r^* \frac{\omega}{\|\omega\|},$

where $\mu_r$ [–] is the non-dimensional coefficient of rolling friction, $\|F_n\|$ [N] is the magnitude of the normal force arising from the contact, $r^*$ [m] is the effective radius, $\omega$ [radians/s] is the angular velocity vector of the particle and $\| . \|$ is the Euclidean norm of a vector.

Warning

Due to the fact that that $M_{r}$ of particle i is not equal to $-M_{r}$ of particle j, since they have different $\omega$ , this model is not recommended for use in a production run. For a discussion on different rolling friction models see Ai et al. (2011). For a good basic rolling friction model see the EPSD2 model.

Coarse-graining information:

Using coarsegraining in combination with this command might lead to different dynamics or system state and thus to inconsistencies.

References

Jun Ai, Jian-Fei Chen, J. Michael Rotter, Jin Y. Ooi, Powder Technology, 206 (3), p 269-282 (2011).