**2.3 Cyclone geometry**

The cyclone geometry considered in the present study is the Stairmand High-Efficiency Cyclone [21], same as that used by Hoekstra [8] in experiments and by Derksen et al. [4] in large-eddy simulations using the lattice-Boltzmann discretization scheme. The choice of cyclone geometry is made keeping in mind the experimental data available facilitating validation of the simulation procedure. The cyclone geometry used for the simulations is presented in **Figure 1**. A similar obstruction with diameter 0.36 Dexit has been provided slightly upstream of the outflow boundary in the present geometry in order to prevent subcritical flow [11].
