# Numerical Results – Lesson 7

### Particle/Vortex Plot

The background is a plot of the vorticity: the Z component of the curl of the velocity field. Red stands for positive value (counterclockwise rotation) and blue stands for a negative value (clockwise rotation). The particles are not plotted in accordance with their actual diameter, but rather a constant of 0.3 for better visual purposes.

From the results below, we can observe maximum coupling between the particles and the vortices at Stokes number = 1. We can observe particles being trapped in the vortices at  Stokes number = 0 condition and ballistic motion of particles at Stokes number = 100. The results for Stokes number = 0.2 and Stokes Number = 5 tend to be more intermediate and less apparent.

Stokes/Time t = 0.5 (s) t = 20 (s) t = 40 (s) t = 60 (s) t = 80 (s)
Stk = 0
Stk = 0.2
Stk = 1
Stk = 5
Stk = 100

### Video of Particle Motion for Stokes = 1 Particles

The video below shows the particle motion when the Stokes number = 1. Maximum coupling between the fluid vortices and the particles can be observed.