Broadband active control of noise and vibration in a fluid-filled pipeline using an array of non-intrusive structural actuators

摘要

Fluid-filled pipelines occur in a wide variety of installations where they are excited bysources such as pumps and compressors through both the structure of the pipe wall and thefluid in the system. These vibrations may propagate downstream and result in unwantedradiated noise from the pipeline or connected structures. Although passive measures areavailable to control both structure and fluid borne vibration, their operating frequencyrange is generally limited by the volume and weight constraints that are imposed by thepractical installation. Active control methods may overcome these volume and weightconstraints and such systems have been investigated for the control of both fluid andstructure borne transmission. In particular, previous work has highlighted the ability tocontrol the internal acoustic pressure using non-intrusive fluid-wave actuators. However,although these systems are able to achieve control of the internal acoustic pressure theyproduce enhancements in the structural vibration and this limits the practical benefit ofthese systems. This paper investigates the behaviour of a non-intrusive structural controllerconsisting of an array of piezo stack actuators positioned circumferentially around the pipeand acting on its outside wall. The ability of the system to control the internal, fluid-borne,acoustic pressure and the externally radiated sound pressure is investigated through aseries of experiments. These results are then used to highlight the trade-off betweencontrolling the internal and external pressures using the non-intrusive array of structuralactuators.