Related Experiment Video
Updated: Jul 4, 2026

The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Shear-induced fluid-tracer diffusion in a semidilute suspension of spheres
Takuji Ishikawa1, Takami Yamaguchi
1Department of Bioengineering and Robotics, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
Abstract:
We calculated tracer diffusion in a sheared suspension of non-Brownian rigid spheres and propose a numerical method based on a boundary element method and Stokesian dynamics method. We present details of the numerical method and examine the accuracy of the method. The limitation of semidiluteness is due to the accuracy of the tracer velocity calculation. The results show that the diffusivity of fluid tracers is greater than that of suspended spheres in the semidilute regime. The diffusivity of the velocity gradient direction is about threefold greater than that in the vorticity direction. Simple scaling demonstrates that the diffusivity of fluid tracers increases with the square of the volume fraction of spheres in the semidilute regime, which is confirmed numerically.
More Related Videos
Related Concept Videos
Newtonian Fluid: Problem Solving
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
Viscosity of Fluid
Stokes' Law
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
Colloids and Suspensions
Types of Fluids
In contrast, non-Newtonian fluids do not follow Newton's law of viscosity, and their...
Steady, Laminar Flow in Circular Tubes

