The TUFLOW Particle Tracking Module (PTM) allows the 2D or 3D simulation of discrete Lagrangian particles as they are transported by the flow field (or other drivers such as wind). Particle behavior such as settling, buoyancy, decay, sedimentation and re-suspension can all be simulated. The tracking of discrete particles can be used to output particle fate and age, which is useful for purposes of animal migration, search and rescue, environmental contaminants and oil spill modelling.
The PTM is invoked through the TUFLOW FV hydrodynamic engine which controls the overall simulation and supplies the hydrodynamic forcing to the particle transport module.
The tutorial will cover a number of aspects of the particle tracking model:
For the purposes of the particle tracking tutorial, we'll be using the hydrodynamic model created in Tutorial Module 5 (Estuary Application) and supplementing with additional information to represent the particles.
Setting up a Point Source of a Group of Particles
Creating a .FVPTM file
The first step in the TUFLOW FV particle tracking module is to generate an .fvptm file which defines the commands to define particle characteristics and processes. This .fvptm file is then referenced via the TUFLOW FV control file (.fvc).
- Use notepad++ to create a new file with extension .fvptm. Name the file PT_000.
- Add the following commands to define a group of particles representing microplastics which enter our model via a combined sewer overflow within our eastuarine reach and can flow out of the model at the downstream tidal boundary.
!PTM to asses fate of Combined Sewer Overflow Outflow ! use nodestring definition from HD model to allow particles to leave model domain. Open boundary nodestring == 2 !downstream tidal boundary !Time Commands langrangian timestep == 60.!seconds eulerian timestep == 60. !seconds !Global Commands Nscalar == 1 !Particle Group Commands
group == microplastics
initial scalar mass == 1000 settling model == none horizontal dispersion model == constant horizontal dispersion parameters == 1.0 vertical dispersion model == HD model vertical dispersion parameters == 1.0 erosion model == none deposition model == none