Taylor-Couette flow is the unique outcome of a centrifugal instability resulting from the rotation of an inner cylinder relative to a concentric outer cylinder. In the simplest and the most practical case where the outer cylinder is fixed, at high enough speed of rotation of the inner cylinder, centrifugal forces overcome viscous forces and donut shaped toroidal vortices fill the space between the cylinders. The vortices are axisymmetric at low speeds of rotation (TVF) but gain an azimuthal waviness with increasing speeds of rotation (WVF).
 

In order to measure the velocity field, Particle Image Velocimetry (PIV) is used. PIV uses a statistical approach, namely a two-dimensional cross-correlation, to measure two-dimensional velocity field within the annulus of the Taylor-Couette flow device. The setup with which the experiments have been conducted is shown. The setup consists of a rotating inner and a stationary coaxial outer cylinder. The illuminated region of interest is viewed by a TSI CCD camera through an acrylic window at the bottom of the cylinders. The illumination is provided by two Nd:Yag lasers each pulsing at 20 Hz and producing green light at 532 nm. 1K x 1K pixel size images are acquired at a rate of 30 Hz. The flow is seeded with silver-coated hallow glass spheres 16 microns in diameter. The captured image pairs are stored in a computer for interrogation and post-processing.
 

Two-dimensional velocity measurements of Taylor-Couette flow have been performed in two planes: a) meridional plane (radial-axial), and b) latitudinal plane (radial-azimuthal). While velocity fields measured in each individual plane provide different aspects of the flow, the combination of the two yields a three-dimensional velocity field. In order to obtain the three-dimensional wavy flow field, the radial component was used to match the velocities measured in each plane.
 

• "Identification of complex flows in Taylor-Couette counter-rotating cavities," Czarny, O, Serre, E, Bontoux, P, and Lueptow, RM, Comptes-Rendus de l'Académie des Sciences Paris, Série IIb - Mécanique / Mechanics, 329: 727-733, 2001.
• "Velocity field for Taylor Couette flow with an axial flow," Wereley, ST, and Lueptow, RM, Physics of Fluids, 11:3637-3649, 1999.
• "Inertial particle motion in a Taylor Couette rotating filter," Wereley, ST, and Lueptow, RM, Physics of Fluids, 11:325-333, 1999.
• "A model of mixing and transport in wavy Taylor-Couette flow," Rudolph, M, Shinbrot, T, and Lueptow, RM, Physica D, 121:163-174, 1998.
• "Spatio-temporal character of nonwavy and wavy Taylor Couette flow," Wereley, ST, and Lueptow, RM, Journal of Fluid Mechanics, 364:59-80, 1998.
• "Hydrodynamic stability of flow between rotating porous cylinders with radial and axial flow," Johnson, EC, and Lueptow, RM, Physics of Fluids. 9:3687-3696, 1997.
• "Stability and experimental velocity field in Taylor Couette flow with an axial and radial flow," Lueptow, RM, in Advances in Couette-Taylor Flows and Related Topics, Springer-Verlag., 2000.