Volume 113, Issue 3, March 2003
Index of content:
- ULTRASONICS, QUANTUM ACOUSTICS, AND PHYSICAL EFFECTS OF SOUND 
113(2003); http://dx.doi.org/10.1121/1.1539521View Description Hide Description
This study concentrates on the reflection of Lamb waves at the free end of a plate. The conversion phenomena are examined in detail over a large frequency range and the energy conversion coefficients are obtained by three different ways: theoretically, numerically (finite element method) and experimentally. The experimental energy determination is obtained from the measurement of the plate normal displacements, by mean of a laser interferometer. All results are in relatively good agreement and the energy balance between incident and reflected waves is discussed in each case.
113(2003); http://dx.doi.org/10.1121/1.1538198View Description Hide Description
Stable cavitation is produced on the surface of a special target, i.e., an abrasive foil with a grain size of about 15 μm, insonified by a 473 kHz focused beam. Cavitation bubbles are first created by a pressure of about 2 MPa. Progressive reduction of the pressure to about 100 kPa leads to a state of stable cavitation characterized by strong stable emission of the half-order subharmonic. This state can be maintained for five hours if the defining parameters (position and pressure) are optimized and constant to within a few percent. There is strong evidence for the presence of “latent” cavitation bubbles, which can persist for a few minutes without being excited.