Driven and freely-decaying nonlinear shape oscillations of drops and bubbles immersed in li【荐】.pdf

b-* DRIVEN AND FREELY-DECAYING NONLINEAR SHAPE OSCILLATIONS OF DROPS AND BUBBLES IMMERSED IN A LIQUID: EXPERIMENTAL RESULTS E.H. Trinh, D.B. Thicssen 1, and R.G. Holt ~ Jet Propulsion Laboratory California Institute of Technology ABSTRACf huge amplitude oscillations of drops and bubbles immersed in an immiscible liquid host have been investigated using ultrasonic radiation pressure techniques. Single levitated or trapped drops and bubbles with effective diameter between 0.4 and 0.8 cm have been driven into resonant shape oscillations of the first few orders. The direct coupling of driven drop shape oscillations between the axisymmetric 1=6 and /=3 modes has been documented as well as the interaction betw=n axisymmetric and non-axisymmetnc modes. Effective resonant coupling from higher to lower order modes has been observed together with a much less efficient energy tmnsfer in the reverse direction. The first three resonant modes for bubbles trapped in water have also been excited, and mode coupling during driven and free-deaiying oscillations has been measured. The evidence gathered thus far indicates that efficient drop resonant coupling from a higher to a lower order mode occurs when the chamcteristic frequency of the latter mode roughly coincides with a h