Active/Passive control of fluid-borne and structure-borne disturbances in fluid-filled piping systems

Energy due to fluid-borne and structure-borne disturbances propagating in a fluid-filled pipe will be carried by the structure and the fluid. Energy transfer may occur between these two media due to the coupling between the structure and the fluid. It's not clear when the excitation is fluid-borne or structure-borne, due to the complexity in piping installation designs and the strong coupling between the fluid and shell walls. It is necessary to devise control approaches that tackle both components of the excitation simultaneously. This study will demonstrate new approaches in active and passive control techniques and show their advantages over classical control approaches. It is necessary to understand the physical behavior of fluid-filled pipes, in order to develop a viable control methodology. The equations of motion for the shell and the fluid are needed to characterize the system. These combined with the dispersion equations can then be used to derive analytical expressions for energy flow in the system. The research is limited to lower order wave types. Hence, the expressions for energy flow are derived only for the n=0 and n=1 shell waves and n=0 fluid wave. Higher order waves have cut-on frequencies and were not analyzed. Current sensing methodologies are limited to the analysis of wave types separately. A new approach of wave decomposition using multiple sensors is developed and used to characterize discontinuities along the pipe. The effect of discontinuities and correct control methodologies are investigated. A new control methodology is developed and implemented. The natural distribution of energy into different wave types as it encounters discontinuities is used to devise control solutions with non-intrusive inertial actuators. Improvements of 16 dB in shell waves and 12 dB in fluid waves over the correct control approach are experimentally demonstrated.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2003

Author dc:creator

• Kiyar, Mustafa Baris

Chairs dc:contributor.committeechair

• Fuller, Christopher R.
• Johnson, Martin E.

Committee member dc:contributor.committeemember

• Kidner, Michael R. F.

• piping systems
• coupled waves
• active control

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-05242004-112951

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/33178