Variable Name Description Units r r distance from the centreline mm z z axial distance from burner surface mm u_mean u_mean Ensemble averaged axial velocity in z direction m/s v_mean v_mean Ensemble averaged radial velocity in r direction - w_mean w_mean Ensemble averaged tangential velocity in azimuthal direction - u' u_rms Ensemble averaged root mean square axial velocity in z direction m/s v' v_rms Ensemble averaged root mean square radial velocity in r direction m/s w' w_rms Ensemble averaged root mean square tangential velocity in azimuthal direction - U_mean U_mean Ensemble averaged absolute velocity m/s U_rms U_mean Ensemble averaged root mean square velocity -