Lift Force Acting on a Heavy Cylinder and a Steady Flow in an Unevenly Rotating Container

摘要

The dynamics of a heavy cylindrical body in a horizontal cylindrical cavity filled with a viscous liquid and subjected to modulated rotation is experimentally investigated. In experiment the cylinders with different moment of inertia are used. Periodic variation (modulation) of cavity rotation rate leads to the azimuthal oscillations of the body in a uniformly rotating reference frame due to viscous interaction with the cavity wall. It is found that near the cavity boundary an averaged repulsive (lift) force acts on an oscillating body. Experiments in a wide range of dimensionless frequency of rotation rate modulation demonstrate that lift force coefficient monotonically growth with frequency increase. The rotation rate modulation is found to be an effective tool to control the behavior of solids located near the rotating wall under microgravity conditions. The analysis of steady velocity field near the oscillating body reveals vortices in form of rolls localized outside the viscous boundary layers.