Standard Rolling Friction
For simulations in which rolling friction is important, this is accounted for by applying a torque to the contacting surfaces.
with μr the coefficient of rolling friction, Ri the distance of the contact point from the center of mass and ωi, the unit angular velocity vector of the object at the contact point.
In EDEM users have the option to include a component of torque arising from rolling friction in geometry torque and power calculations. This component of torque is neglected (Off) by default.
Users can select to include or neglect this component of torque by clicking the 
button on the selected Particle to Geometry contact model. The tick box is unchecked by default, checking the “Apply the torque resulting from the rolling friction model to the geometry elements” option includes the torque same as EDEM 2017 and earlier.
Note: Prior to EDEM 2018 this component of torque was included (On) by default. Including it means geometry torque and power calculations are mesh size sensitive. Particle behavior is not influenced by including or neglecting this component of torque.