Cyclone separators are used in a variety of industries for efficient separation of mixtures of fluid and solid phases. In collaboration with Dyson, the focus of this research has been to address the inherent instability of highly swirling flow and understand the dynamics of how these oscillations are generated.
The specific application of this research is to the small domestic vacuum cleaner cyclones, which generate very tonal noise within the sensitive range of human hearing. Cyclones are well known to have a fluid instability characterised by a precessing vortex core resulting from the combination of axial velocity reversal and strong swirling flow.
Employing linear analysis to local regions of the flow highlights how small perturbations grow and decay with time and build a picture of the globally oscillating system.
Current work is focused on developing understanding of the coupling between the fluid dynamics and acoustic generation and incorporating novel methods of control to the system.