July 2, 2011

Scientists Crack Secret To Mysterious Tibetan Singing Bowls

Scientists have cracked the secret to what makes Tibetan "singing bowls" so mysterious.

The water-filled bowls are rubbed with a leather-wrapped mallet to exhibit a haunting sound, creating strange waves.

A Tibetan bowl is generally made from a bronze alloy containing copper, tin, zinc, iron, silver, gold and nickel.

The Faraday waves arise when a fluid like water vibrates, constrained by a closed boundary like the edge of the bowl.

As the frequency of the rubbing reaches at which the bowl naturally vibrates, the bowl's edge begins rhythmically to change shape, from one slightly oval shape into another.

The energy of this shape-shifting partly transfers to the water, in which a range of interesting patterns can arise as the intensity of the rubbing increases.

However, at a certain point the water becomes unstable, which results into a fizzing display of droplets and chaotic waves. 

John bush from the Massachusetts Institute of Technology, along with colleagues from the Universit© de Lige, used a high-speed video of that transition to demonstrate how the irregular patterns of waves build up, the way that they crash into one another, and how that frees droplets that fly into the air.

Droplets can actually bounce repeatedly and skip on the surface of the water under certain conditions.

A high-speed camera was used to capture images of the droplets, from which measurements could be taken.

The researchers have developed a mathematical model for how the water behaves in the bowls.

Studies of this are potentially of broader interest for applications in which the development of tiny fluid droplets is a concern.

Senior author Professor Bush said in a statement, "Although our system represents an example of fluid-solid interactions, it was motivated more by curiosity than engineering applications.

"We are satisfied with the results of our investigation, which we feel has elucidated the basic physics of the system. Nevertheless, one might find further surprises by changing the bowl or fluid properties."

The research was published in the journal Nonlinearity.


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