Particle Tracking Workflow

Particle tracking in combination with isochrone markers or period sections can be used to evaluate the flow paths and flow times.

Particle tracking is included in FEFLOW as a visualization option for the active view window. Showing the traces of particles is done in the following steps:

• Define the starting location (s)

• Choose the type of field lines

• Add the traces to the view

• Edit the field-line properties

• Choose visualization style

Field-line visualization is only possible when a calculated fluid-flux field (Darcy velocities) is available. This is the case while running the simulation, when the simulation is paused, and in case a full results file (*.dac) is loaded.

Define the Starting Location (s)

Starting locations for field lines can be defined as points or lines. Starting points can be derived from Domain Locations or Stored Node Selections in the Selections panel. Alternatively, the Current Node Selection in the Selections panel can be used. Select seed nodes... and Draw seed line/points... in the context menu of the Streamlines and Pathlines entries in the Data panel provide quick access to the selection and drawing tools.

Domain Locations can be created by using one of the following options:

• Using the tools in the Drawing toolbar

• Converting maps into location sets via the context menu of corresponding maps in the Maps panel

• Using Import location Set in the context menu in the Entities panel.

The following table shows examples for starting locations:

	Node selection
	3D Polyline
	3D Loop
	3D Point Group

Domain Locations may be given customized names by choosing Rename or Edit from their context menu.

Select the Domain Location to be used as starting location (s) for streamline visualization by clicking on it in the Entities panel.

Choose the Type of Field Lines

Four types of field lines are listed in the Process Variables > Fluid flow section of the Data panel:

• Streamlines: Forward or Backward

• Pathlines: Forward or Backward

Choose the type of field lines to be visualized by double-clicking the corresponding entry in the Data panel.

Add the Traces to the View

With the double click on the parameter in the Data panel the field lines are calculated and added to the View Components panel. The traces are drawn in the active view if the checkmark in front of Traces is set in the View Components panel.

Period Sections and Isochrone Markers can be shown by checking the corresponding check box in the tree of the View Components panel.

When Current Selection is used as the starting point geometry, additional nodes may be selected after making the traces visible. Thus, streamlines/pathlines can be added interactively.

 

Which FEFLOW parameter should be used as effective porosity for the streamline/pathline computation can be defined in the Problem Settings dialog. The option Edit Field-Line Computation Settings in the context menu of the Streamlines/Pathlines, Forward, and Backward entries in the Data panel provides quick access to this setting.

Edit the Field-line Properties

Options for the streamline/pathline display such as colouring, number of streamlines/pathlines, radius for multiple streamlines/pathlines, etc. are defined as visualization properties.

A double click on the Travel time group entry in the View Components panel or on Properties in its context menu brings the Properties panel to front, allowing the following settings:

• Selection of the color scheme,

• Definition of minimum or maximum flow time, limiting pathline length and influencing the colouring,

• Selection of the seed time for pathlines,

• Selection of the number of seeds,

• Enabling flux-weighted or equally spaced starting distribution,

• Definition of the starting radius around the starting location.

The changes are applied by pressing the Apply button.

 

The starting radius around the starting points is defined in the x-y plane and is not bound to a slice. Thus, although working in the Slice view some particles might start in a layer located above or below the current slice. If the material properties in adjacent layers differ significantly, quite different field lines may result depending on which layer the tracking starts in.

Choose Visualization Style

The field lines feature three visualization options in the View Components panel: Traces, Period Sections, and Isochrone Markers:

• Traces visualize the particle trajectories with a continuous colouring representing the travel time.

• Period Sections provide a view of the trajectories in sections defined by intervals of travel time.

• Isochrone Markers can be used to mark locations along the trajectories representing a specific travel time.

The Properties panel for the different visualization options is brought up front by double-clicking one of the options in the View Components panel or via its context menu. It provides the following options:

 

Traces	Size, Legend
Period Sections	Size, Iso (travel time intervals), Legend
Isochrone Markers	Size, Iso (travel time stages), Legend, Light