Self-propulsion of a counter-rotating cylinder pair in a viscous fluid

Self-propulsion of a counter-rotating cylinder pair in a viscous fluid

Propulsion and Instability of a Flexible Helical Rod Rotating in a Viscous Fluid.

We combine experiments with simulations to investigate the fluid-structure interaction of a flexible helical rod rotating in a viscous fluid, under low Reynolds number conditions. Our analysis takes into account the coupling between the geometrically nonlinear behavior of the elastic rod with a nonlocal hydrodynamic model for the fluid loading. We quantify the resulting propulsive force, as wel...

Circular band formation for incompressible viscous fluid-rigid-particle mixtures in a rotating cylinder.

In this paper we have investigated a circular band formation of fluid-rigid-particle mixtures in a fully filled cylinder horizontally rotating about its cylinder axis by direct numerical simulation. These phenomena are modeled by the Navier-Stokes equations coupled to the Euler-Newton equations describing the rigid solid motion of the non-neutrally particles. The formation of circular bands stu...

Self-propulsion of a spherical electric or magnetic microbot in a polar viscous fluid.

The self-propulsion of a sphere immersed in a polar liquid or ferrofluid is studied on the basis of ferrohydrodynamics. In the electrical case an oscillating charge density located inside the sphere generates an electrical field that polarizes the fluid. The lag of polarization with respect to the electrical field due to relaxation generates a time-independent electrical torque density acting o...

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

Results are reported of an experimental investigation into the motion of a heavy cylinder free to move inside a water-filled drum rotating around its horizontal axis. The cylinder is observed to either co-rotate or, counter-intuitively, counter-rotate with respect to the rotating drum. The flow was measured with particle image velocimetry, and it was found that the inner cylinder significantly ...