Fountain Effect

Fountain effect images at a water-air boundary produced by an ultrasound field normally incident to the boundary with the focus at the boundary. Ultrasound source has a 3.32-MHz center frequency, a 6-cm diameter, and an f-number of 2.25. The free-field -6-dB pulse-echo beamwidth at the focus is 6.7 mm. The free-field in vitro peak rarefactional pressures (left to right, then up to down) are 0.6, 1.1, 1.4, 1.5, 1.6, 1.8, 2.0, 2.2 and 2.5 MPa, and the respective temporal-average intensities at the focus are 1.15E-4, 2.18E-4, 4.97E-4, 7.05E-4, 9.38E-4, 1.51E-3, 1.92E-3, 2.65E-3, and 3.70E-3 W/m2. The pulse duration is 12.4µS and the pulse repetition frequency is 1 kHz.

Photos taken by Chief Photographer, James P. Blue Jr. This work was supported by NIH Grant HL58218.

This is a figure showing the correlation between the distance the transducer is from the surface water surface and the required voltage to break the water surface. Where the voltage is the lowest, corresponds to the focal distance of the transducer.

Future studies hope to relate this Fountain Effect to the Lung Damage Project.