Related Experiment Video
Updated: Jul 17, 2026

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence
Published on: June 24, 2016
Direct observation of hydrodynamic rotation-translation coupling between two colloidal spheres
S Martin1, M Reichert, H Stark
1Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany.
Abstract:
By combining optical tweezers with polarization microscopy, the hydrodynamic coupling between position and orientation fluctuations in a pair of colloidal spheres has been measured. Imaging of birefringent particles under crossed polarizers allows for the simultaneous determination of the positions and orientations of both particles. The temporal cross-correlation function between random displacements of one particle and orientation fluctuations of its neighbor allows for the quantification of the hydrodynamic rotation-translation coupling between the spheres. Our results are in good agreement with predictions for the hydrodynamic mobility tensors calculated in the creeping-flow limit of the Navier-Stokes equation.
Related Concept Videos
Colloids and Suspensions
Colloids
Steady, Laminar Flow Between Parallel Plates
Colloidal precipitates
The Colloidal State
Fluid Mosaic Model

