A simple zero-velocity method to determine the particle magnetic susceptibility by measuring the magnetophoretic velocity was proposed. The principle is that the magnetophoretic velocity of a particle in a liquid medium must be zero when the magnetic susceptibilities of the medium and the particle are equal, or the gravity force and the magnetophoretic force are balanced. By changing the medium...

As we all know, when the relative velocity of two inertial reference frames ∑ and ∑′ is less than the speed of light, the relations of xμ with x ′ μ, a particle mass m with its velocity υ, and a particle mass with its energy are all given by Einstein’s special relativity. In this paper, we will give new relation of xμ and x ′ μ when the relative velocity of ∑ and ∑′ frame is larger than the spe...

A shear flow of particles in a laser-driven two-dimensional (2D) dusty plasma is observed in a study of viscous heating and thermal conduction. Video imaging and particle tracking yields particle velocity data, which we convert into continuum data, presented as three spatial profiles: mean particle velocity (i.e., flow velocity), mean-square particle velocity, and mean-square fluctuations of pa...

The effective equation describing the transport of passive tracers in nonsolenoidal velocity fields is determined, assuming that the velocity field U(r,t) is a function of both position r and time t, albeit remaining locally random. Assuming a strong separation of scales and applying the method of homogenization, we find a Fickian constitutive relation for the coarse-grained particle flux, as t...

This paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our...

To solve the problem that the parameters in grey neural network (GNN) are difficult to determine, the improved Particle Swarm Optimization (IPSO) algorithm is employed to search the optimums by the introduction of a threshold of velocity. When the particle velocity is less than the threshold, an accelerated momentum is applied on the particle to reinitialize the particle velocity and position. ...

Particle image velocimetry and a 3D hard sphere discrete particle model were applied to determine particle velocity profiles in the plane around a spout in a spoutfluid bed for various initial bed heights, spout and background fluidization velocities. Comparison between experimental and numerical results revealed that the particle velocities are underestimated by particle image velocimetry, whi...

In this paper we have studied the migration of a colloidal particle under the influence of an external electric field in an electrolyte solution. The colloidal particle is considered to be rigid or a composite particle. The composite particle, the “soft particle”, consist an inner hard core coated with a concentric porous layer containing uniformly distributed fixed charges. Situations in which...

In this paper, the transient settling dynamics of a spherical particle sedimenting in a linearly stratified fluid is investigated by performing fully resolved direct numerical simulations. The settling behaviour is quantified for different values of Reynolds, Froude and Prandtl numbers. It is demonstrated that the transient settling dynamics is correlated to the induced Lagrangian drift of flow...

Velocity errors in particle tracking velocimetry (PTV) are studied. When using high-speed video cameras, the velocity error may increase at a high camera frame rate. This increase in velocity error is due to particle-position uncertainty, which is one of the two sources of velocity errors studied here. The other source of error is particle acceleration, which has the opposite trend of diminishi...