B. U. Felderhof

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A matrix formulation is derived for the calculation of the swimming speed and the power required for swimming of an assembly of rigid spheres immersed in a viscous fluid of infinite extent. The spheres may have arbitrary radii and may interact with elastic forces. The analysis is based on the Stokes mobility matrix of the set of spheres, defined in low(More)
  • B U Felderhof
  • Physical review. E, Statistical, nonlinear, and…
  • 2014
Velocity relaxation of an elastic sphere immersed in a viscous incompressible fluid is studied on the basis of the equations of linear elasticity and the linearized Navier-Stokes equations. It is found that both translational motion after a sudden impulse and rotational motion after a sudden twist show jittery behavior in the long-time regime, with many(More)
  • B U Felderhof
  • Physical review. E, Statistical, nonlinear, and…
  • 2012
The hydrodynamic force on a particle oscillating in a viscous fluid near a wall with partial-slip boundary condition is studied on the basis of the linearized Navier-Stokes equations. Both incompressible and compressible fluids are considered. It is assumed that the slip length characterizing the partial-slip boundary condition depends on frequency. The(More)
  • B U Felderhof
  • Physical review. E, Statistical, nonlinear, and…
  • 2015
A mechanical model of swimming and flying in an incompressible viscous fluid in the absence of gravity is studied on the basis of assumed equations of motion. The system is modeled as an assembly of rigid spheres subject to elastic direct interactions and to periodic actuating forces which sum to zero. Hydrodynamic interactions are taken into account in the(More)
Brownian motion of a particle situated near a wall bounding the fluid in which it is immersed is affected by the wall. Specifically, it is assumed that an incompressible viscous fluid fills a half-space bounded by a plane wall and that the fluid flow satisfies stick boundary conditions at the wall. The fluctuation-dissipation theorem shows that the velocity(More)
Escape by diffusion in one dimension from a parabolic well across a parabolic barrier is investigated for a range of barrier heights. The probability of occupation of the well decays at long times inversely with the square root of time due to repeated return to the well after excursion in the outer space. The amplitude of the long-time tail increases as the(More)
  • B U Felderhof
  • Physical review. E, Statistical, nonlinear, and…
  • 2001
The magnetoviscosity of a ferrofluid flowing down a circular tube in the presence of a magnetic field oscillating in the direction of the axis is studied on the basis of ferrohydrodynamics, Maxwell's equations of magnetostatics, and a relaxation equation for the magnetization. Three different relaxation equations, proposed in the literature, are considered.(More)
The method employed by Einstein to derive his famous relation between the diffusion coefficient and the friction coefficient of a Brownian particle is used to derive a generalized Einstein relation for the mutual diffusion coefficient of a binary fluid mixture. The expression is compared with the one derived by de Groot and Mazur from irreversible(More)