Acoustic Analysis - Flow Induced Vibration

Acoustic analysis is the study of various acoustic phenomena in piping and structural systems that can result in acoustic induced vibration due to acoustic exciters such as valves, ducts, and cavities (shallow or deep).Acoustic analysis is necessary to identify any potential sources of acoustic induced vibration in a given system and design a solution to mitigate the potential effects, typically failure through fatigue.  Acoustic resonance is the main phenomena of concern and it is induced by a gaseous fluid flow, typically but not limited AcousticHarmonics.pngto air or steam. Issues that result from acoustic phenomena have been observed in power (nuclear, fossil), oil and gas and industrial systems. Acoustic resonance can lead to flow induced vibration. Different acoustic phenomena often present themselves in systems and go unnoticed until there is a failure in the system. Examples of acoustic phenomena are column resonance, Helmholtz resonance and trapped mode acoustics.

Illustration of vortex shedding (an acoustic resonance exciter) across a valve cavity and the acoustic pressure waves that result; these waves can act as loads on components in a system and lead to cyclic fatigue failure. 

BENEFITS

It is essential to understand the potential for acoustic resonance issues when designing a new system or upgrading an existing system especially if the system failure is a safety concern or if the system failure could affect productivity. It is also recommended when a system with potential excitation sources was designed without acoustic phenomena taken into account or when a system is being upgraded.

Fauske & Associates, LLC (FAI) studies acoustic resonance issues using acoustic analysis to screen and analyze subject systems as well as experiments if necessary to verify the results.

SOLUTIONS/EXPERTISE

Samad_Pipe Clamp InstallationFAI has a broad range of expertise in this area gained from working on acoustic resonance issues in the nuclear, fossil and chemical process industry.  Our screening analysis and tests address key issues including: 

  • Identification of systems that have potential excitation sources
  • Determining if a system failure with potential sources was actually caused by acoustic resonance
  • Satisfaction of industry regulatory guide or standard requirement such as those included in the Nuclear Regulatory Commission (NRC) Reg. Guide 1.20 
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You can obtain mode shapes using the co-quad and global least squares method

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