Related Experiment Video
Updated: May 21, 2026
10:03
Uncoupling Coriolis Force and Rotating Buoyancy Effects on Full-Field Heat Transfer Properties of a Rotating Channel
Published on: October 5, 2018
Drift velocity in non-isothermal inhomogeneous systems
Mingcheng Yang1, Marisol Ripoll
1Theoretical Soft-Matter and Biophysics, Institute of Complex Systems, Forschungszentrum Jülich, 52425 Jülich, Germany. m.yang@fz-juelich.de
The Journal of Chemical Physics
|June 7, 2012
Summary
In inhomogeneous suspensions, drift velocity and driving force aren't directly proportional. Particle flux also depends on self-diffusion gradients, challenging existing approximations in mass transport.
Area of Science:
- Physics
- Physical Chemistry
- Materials Science
Background:
- Inhomogeneous suspensions exhibit complex transport phenomena.
- Traditional models often assume direct proportionality between drift velocity and driving force, which may not hold true.
Purpose of the Study:
- To investigate the relationship between drift velocity, driving force, and particle flux in inhomogeneous suspensions.
- To explore the influence of space-dependent mobility and self-diffusion gradients on mass transport.
- To validate simulation findings against theoretical approximations.
Main Methods:
- Computer simulations of a non-equilibrium system.
- Inclusion of a temperature gradient to induce mass transport.
- Analysis of space-dependent mobility and self-diffusion coefficients.
Main Results:
- Drift velocity is not directly proportional to the driving force in inhomogeneous suspensions due to space-dependent mobility.
- Particle flux is influenced by both density and self-diffusion coefficient gradients.
- The thermal diffusion coefficient is not directly proportional to drift velocity, indicating approximations in current theories.
Conclusions:
- The direct proportionality between drift velocity and driving force is an approximation for inhomogeneous systems.
- Self-diffusion gradients play a crucial role in particle flux.
- Simulation results highlight the limitations of simplified models in describing complex mass transport phenomena.
Related Concept Videos
01:19Drift Velocity
The high speed of electrical signals results from the fact that the force between charges acts rapidly at a distance. Thus, when a free charge is forced into a wire, the incoming charge pushes other charges ahead due to the repulsive force between like charges. These moving charges move the charges farther down the line. The density of charge in a system cannot easily be increased, so the signal is passed on rapidly. The resulting electrical shock wave moves through the system at nearly the...
01:21Carrier Transport
The generation of electrical current in semiconductors is fundamentally driven by two mechanisms: drift and diffusion. These processes are essential for the functionality and performance of semiconductor-based devices.
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:
01:11Velocity and Acceleration in Steady and Unsteady Flow
In fluid mechanics, velocity and acceleration are key concepts for analyzing particle motion in both steady and unsteady flow. Consider a fluid particle moving along a pathline, where its velocity depends on its position and time. The particle's acceleration is obtained by differentiating the velocity with respect to time.
The acceleration can be generalized to any point in the flow, and expressed as components along three perpendicular directions, representing changes in velocity over time.
The acceleration can be generalized to any point in the flow, and expressed as components along three perpendicular directions, representing changes in velocity over time.
01:20Velocity Potential
In steady, incompressible flow through a long, straight pipe with a uniform cross-section, the flow in the central region (far from the pipe walls) is irrotational. This irrotational nature means that fluid particles do not rotate around their axes, and a scalar function called the velocity potential, represented by ϕ, can be used to describe their movement. In irrotational flows, the velocity field V is defined as the gradient of the velocity potential:
01:28Navier–Stokes Equations
For incompressible Newtonian fluids, where density remains constant, stresses show a linear relationship with the deformation rate, defined by normal and shear stresses. Normal stresses depend on the pressure exerted on the fluid and the rate of deformation in specific directions, which determines how fluid flows under varying pressures. Shear stresses, on the other hand, act tangentially across fluid layers. They explain how adjacent fluid layers slide relative to one another, connecting...
01:17Theory of Metallic Conduction
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...