Abstract

A cyclone separator is a flow device used to separate particles from a fluid by centrifugal forces in a rapidly swirling flow. They are very effective because they do not use filters. Cyclones are known to generate narrow-band noise centred around one or more distinct frequencies. We will refer to the noise as a cyclone hum. This hum is hypothesised to be a result of oscillations of the vortex core. For small cyclones this hum presents as unwanted noise, however in larger industrial units, the oscillations can lead to structural damage. In this talk we will see how the oscillations are produced, how it leads to noise and what we could be done to suppress the oscillations. The method of examining the oscillations could be applied to other swirling systems like the flow within combustion chambers.