Selection of topics:
Particle-laden pipe flow
The turbulent drag reduction in particle-laden pipe flow (Toms effect) is explained in the corresponding paper (Vreman 2007, see publication page). The first movie shows the particles in the boundary layer (volume fraction 1.5%). The color refers to the location in the pipe (radius). Only colliding particles are shown, during short time intervals around the collisions. In the second movie small heavy particles are shown on top of the tangential gas velocity in a cross section of the pipe (case with volume fraction 0.005%).
Two other movies can be downloaded. They show the trajectories of a few randomly chosen particles, projected on a cross section of the pipe (circle). A red flash means a collision with another particle, while a yellow flash means a collision with the boundary.
Movie pipe flow with a particle volume fraction of 0.01% (13Mb)
Movie pipe flow with a particle volume fraction of 1.5% (10Mb)