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.

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Sound from blowing a conch shell is known for its tonal quality. Its use in many cultures is known. In Hindu culture, conch shell is blown on several auspicious occasions such as festivals, worship, and rituals. A conch shell can be modeled as a horn in its acoustical behavior. This work presents an acoustical study in terms of the spectral characteristics of the shell. The study also presents the influence of parameters such as placing hand in the mouth of the conch shell and the size of conch shell on the spectral characteristics.

Acoustics has received a very high importance in the Vedic Hindu tradition and philosophy of ancient India. The Vedic literature which refers to both the Vedas and the subsequent literature based on Vedas emphasize that the roles of sound both as source signal and as hearing are important. This work presents the various ways such as chants, Sanskrit language, vocal, and instrumental music in which acoustics has played a major role.

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