# 8.2.5. slidingInterfaces#

## 8.2.5.1. axisOfRotation#

The rotation of a sliding interface follows the right hand rule. The fingers follow the spinning of the sliding interface and the thumb points to the axisOfRotation. Left handed rotations can be simulated by entering a negative omega.

## 8.2.5.2. omega#

For convenience, there are two options for prescribing the nondimensional rotation speed in the Flow360.json file. Users can either input omegaRadians or omegaDegrees according to the units of their physical rotation speed $$\Omega$$:

(8.2.5)#\begin{align}\begin{aligned}\text{omegaRadians} = \Omega \ \text{(rad/s)} \cdot \frac{L_\text{gridUnit}}{C_\infty}\\\text{omegaDegrees} = \Omega \ \text{(deg/s)} \cdot \frac{L_\text{gridUnit}}{C_\infty}\end{aligned}\end{align}

See this example showing how to obtain nondimensional omega from RPM and this tutorial for an unsteady isolated rotor case using a sliding interface.