which is useful to generate particles in particular shapes (as in this
example), or to transfer information between two different computational grids
(as in step-70). Furthermore, the Particles::ParticleHandler class provides the
-Particles::ParticleHandler::insert_global_particles function() which enables the
+Particles::ParticleHandler::insert_global_particles() function which enables the
global insertion of particles from a vector of arbitrary points and a global
vector of bounding boxes. In the present step, we use the
Particles::Generators::quadrature_points() function on a non-matching triangulation to
-insert particle located at positions in the shape of a disk.
+insert particles located at positions in the shape of a disk.
<h4>Particle exchange</h4>
<h3>The testcase</h3>
In the present step, we use particles as massless tracers to illustrate
-the dynamics of a particular vortical flow: the Rayleigh-Kothe Vortex. This flow pattern
+the dynamics of a particular vortical flow: the Rayleigh--Kothe vortex. This flow pattern
is generally used as a complex test case for interface tracking methods
(e.g., volume-of-fluid and level set approaches) since
it leads to strong rotation and elongation of the fluid @cite Blais2013.
The stream function $\Psi$ of this Rayleigh-Kothe vortex is defined as:
@f[
-\Psi = \frac{1}{\pi} sin^2 (\pi x) \sin^2 (\pi y) \cos \left( \pi \frac{t}{T} \right)
+\Psi = \frac{1}{\pi} \sin^2 (\pi x) \sin^2 (\pi y) \cos \left( \pi \frac{t}{T} \right)
@f]
where $T$ is half the period of the flow. The velocity profile in 2D ($\textbf{u}=[u,v]^T$) is :
@f{eqnarray*}
capacity to be used in distributed parallel simulations. However, this step could
be extended in numerous manners:
- High-order time integration (for example using a Runge-Kutta 4 method) could be
-used to increase the accuracy and allow for an increased time-step size.
+used to increase the accuracy or allow for larger time-step sizes with the same accuracy.
- The full equation of motion (with inertia) could be solved for the particles. In
this case the particles would need to have additional properties such as their mass,
as in step-19, and if one wanted to also consider interactions with the fluid, their diameter.