The fluid dynamics of Tibetan singing bowls

BBC : Researchers have developed a mathematical model to describe the acoustics and fluid dynamics of water in ceremonial Tibetan singing bowls. According to John Bush of MIT and Denis Terwagne of Belgium’s University of Liege, who yesterday published a paper in the journal Nonlinearity, “rubbing a fluid-filled bowl excites wall vibrations, and concomitant waves at the fluid surface” much like what occurs when a wine glass is rubbed by a moist finger. However, the waves in Tibetan singing bowls—called edge-induced Faraday waves—exhibited behavior that is “odd by any standards, even to specialists in fluid dynamics,” said Bush. At a certain point the waves become chaotic, causing water droplets to break free and bounce on the water’s surface. Bush and Terwagne found that the relatively low vibration frequency of the bowls makes them a more efficient generator of edge-induced Faraday waves and droplet generation via surface fracture. Their research could shed light on other fluid processes, such as fuel injection.