Drag and lift forces on a counter-rotating cylinder in rotating flow

Abstract

Results are reported of an experimental investigation into the motion of a heavy cylinder free to move inside a water-filled drum rotating around a horizontal axis. The cylinder is observed to either co-or, counter intuitively, counter-rotate with respect to the rotating drum. The flow was measured with particle image velocimetry (PIV), and it was found that the inner cylinder significantly altered the bulk flow field from the solid-body rotation found for a fluid filled drum. In the counter-rotation case, the generated lift force allowed the cylinder to freely rotate without contact with the drum wall. Drag and lift coefficients of the freely counter-rotating cylinder were measured over a wide range of Reynolds numbers, 2,500 < Re < 25,000, dimensionless rotation rates, 0.0< α <1.2, and gap to cylinder diameter ratios 0.003 < G/2a < 0.5. Drag coefficients were consistent with previous measurements on a cylinder in a uniform flow. However, for the lift coefficient considerable larger values were observed in the present measurements. We found the enhancement of the lift force to be mainly caused by the vicinity of the wall.

Applying laser Doppler anemometry inside a Taylor–Couette geometry using a ray-tracer to correct for curvature effects

“…For a large range of Reynolds numbers it is known that vortices will be shedded [19] from these probes, either in form of a Kármán vortex street or as a turbulent wake, depending on the geometry and Reynolds number. These vortices can survive a full revolution, which has been observed in rotating drum experiments [20].…”

Role of viscous friction in the reverse rotation of a disk

“…We now turn our attention to the geometric parameter defined in (6). In the absence of friction, we found that reverse rotations are possible only if H < 0.793 = H c (0), according to (9). Although perennial reverse rotations are not present for b = 0, one may ask which values of H allow for transient reverse behavior.…”

“…Famous examples of such a phenomenon are * pablo@df.ufpe.br † parisio@df.ufpe.br the reverse, or retrograde, rotations of Venus [5][6][7] and Uranus [5]. Behaviors belonging to the same class can be found in the dynamics of rolling cylinders immersed in viscous fluids [8][9][10] and in the chaotic response of a damped pendulum parametrically excited [11]. From a more applied point of view, reverse rotations may appear, being potentially deleterious, in bearings of journal machinery [12].…”

Spinning Rigid Bodies Driven by Orbital Forcing: The Role of Dry Friction

“…Dynamical behaviors where the spinning and orbital rotations of a body are antiparallel are dubbed reverse rotations (RRs). Examples include bodies inside rotating chambers filled with viscous fluids [5][6][7], the parametrically-excited damped pendulum [8], the dynamics of bearings of journal machinery [9], chiral active particles [10], and the problem of biological tissue production. In the latter, a common method to generate tissue is the rotating vessel bioreactor, which consists of a container filled with a nutrient-rich medium rotating about its longitudinal axis at constant angular speed.…”