Acoustic beams can exert radiation forces and/or torques on objects, allowing, for example, manipulation of cells in suspension, assessment of viscoelastic properties of biological tissues, and targeted drug and gene delivery. I will present analyses of forces and torques exerted by acoustic beams on spheres.
A stable liquid cylinder can be supported in zero gravity by a helical spring that constrains the free surface against instability. This capillary channel geometry has potential applications for liquid control and containment in low gravity. I will present a theoretical study of the capillary wave dynamics in periodically supported structures.