Incompressible Squeeze-Film Levitation

TL;DR

This paper investigates the phenomenon of levitation caused by transverse vibrations in incompressible fluids, revealing the physical law governing steady-state levitation height and resolving discrepancies with classical lubrication theory.

Contribution

It uncovers the main source of pressure asymmetry in incompressible thin films and establishes the governing physical law for levitation height, confirmed through experiments.

Findings

Pressure asymmetry explains levitation in incompressible fluids.

Physical law for steady-state levitation height is derived.

Experimental validation confirms theoretical predictions.

Abstract

Transverse vibrations can induce the non-linear compression of a thin film of air to levitate objects, via the squeeze film effect. This phenomenon is well captured by the Reynolds' lubrication theory, however, the same theory fails to describe this levitation when the fluid is incompressible. In this case, the computation predicts no steady-state levitation, contradicting the documented experimental evidence. In this letter, we uncover the main source of the time-averaged pressure asymmetry in the incompressible fluid thin film, leading the levitation phenomenon to exist. Furthermore, we reveal the physical law governing the steady-state levitation height, which we confirm experimentally.