A rigid dumbbell settling under gravity in a periodic flow field

PIVA, M.; MARTINO, R.

JOURNAL OF PHYSICS. A - MATHEMATICAL AND GENERAL

Institute of Physics

Año: 2008 vol. 42 p. 1 - 1

0305-4470

he motion of a rigid dumbbell settling under gravity in a stationary twodimensionalcellular flow field is investigated. The dumbbell is modeled astwo identical beads connected by a rigid rod. Assuming that the bead radiusis much shorter than the bead to bead distance, a simple model is obtainedto describe the dynamical behavior of the dumbbell in terms of evolution ofthe dumbbell orientation and the velocity of the center of mass. The averagevelocity of the dumbbell in the gravity direction was found to depend on thedumbbell length, the inertia parameter and the terminal settling velocity in stillfluid. For certain conditions the dumbbell remains suspended in the flow field.In one of the suspension regimes the dumbbell remains indefinitely attached toa fixed point. This behavior is related to the existence to saddle nodes in thecellular flow field.