Acoustics of Corrugated Pipes: A Review

Corrugated pipes and tubes are commonly used in many engineering and industrial applications because they offer global flexibility combined with local rigidity. Some of the engineering systems which use the corrugated pipes are Liquefied Natural Gas (LNG) storage systems, risers for offshore oil and gas industries, heat, ventilation, and air conditioning systems (HVAC), aerospace and automobile cabin cooling systems, and certain domestic appliances such as vacuum cleaners. Air flow through a short or a long length of corrugated pipes can cause the pipes to emit loud and clear “tonal” sounds or “whistling” at some critical flow conditions. Interaction and coupling of these acoustic waves with vortex shedding-flow instability can result in severe noise and structural vibration problems. A phenomenon of sound generation in corrugated pipes is also observed in a children's toy called “Hummer,” “Voice of the Dragon,” or “Magic Whistle.” This review paper focuses on the research work carried out to date to study the sound generation mechanism and its reduction methodology in corrugated pipes with air flow. This paper reviews and summarizes the various theoretical, experimental and computational work carried out in relation to acoustics of corrugated pipes.