The motion of a sphere in the presence of a fluid-fluid interface is studied. First, a solution is derived for a point force near a plane interface. Then the solution is extended to include the higher-order terms which are required to describe the motion of a solid sphere. Singularities of higher orders at the centre of the sphere are obtained by using the method of reflexions. For a fluid-flui...

M. S. Howe J. Fluid Mech. 206, 131 1989 presented integral formulas for the force and torque on a rigid body that permit the identification of the separate influences of added mass, normal stresses induced by free vorticity, and viscous skin friction. Here a simple extension of Howe’s formulas is done for systems of several rigid bodies. The goal is to separate these effects on each rigid body....

This paper describes a dynamic system-a system that develops order only when dissipating energy-comprising millimeter to centimeter scale gears that self-assemble into a simple machine at a fluid/air interface. The gears are driven externally and indirectly by magnetic interactions; they are made of poly(dimethylsiloxane) (PDMS) or magnetically doped PDMS, and fabricated by soft lithography. Tr...

The drag anisotropy of slender filaments is a critical physical property allowing swimming in low-Reynolds number flows, and without it linear translation is impossible. Here we show that, in contrast, net rotation can occur under isotropic drag. We first demonstrate this result formally by considering the consequences of the force- and torque-free conditions on swimming bodies and we then illu...

Simulation of an underwater glider to investigate the effect of angle of attack on the hydrodynamic coefficients such as lift, drag, and torque. Due to the vital role of these coefficients in designing the controllers of a glider and to obtain an accurate result, this simulation has been studied at a range of operating velocities. The total length of the underwater glider with two wings is 900 ...

introduction: the purpose of this study was to compare the accuracy of the torque wrenches used in different dental implant systems. methods: we evaluated 42 torque wrenches used in different dental clinics in mashhad, iran, using a digital torque meter (mark 10). high (25, 30 and 35 n·cm) and low (15 n·cm) levels of torque were examined. ten tests were performed on each wrench, and the mean va...