Look at this buoyancy experiment. Forcing an inverted immiscible oil layer to suspend by applying a vibration to an injected air layer underneath this layer. This vibration prevents a Rayleigh–Taylor instability (i.e. glob dripping) from collapsing the layer.

https://youtu.be/gAsDcS-QW_U

\$${\displaystyle {\frac {d^{2}y}{dt^{2}}}+(a-2q\cos 2t)y=0,} \$$