Standard Pathlines

Standard Pathlines are trajectories of individual fluid particles over a certain time period. At each moment in time, the direction of the pathline is determined from the direction of the velocity vectors at this time; the flow velocity is determined by the magnitude of the velocity vector at this time.

Pathlines end at model boundaries or when the travel time limit is reached (current simulation time for forward pathlines, simulation start time for backward pathlines) or in a part of the domain where the flow velocity is close to zero.

The steps necessary for displaying pathlines are described in the Particle Tracking Workflow.

• Forward: Using the forward option, pathlines are started from the seeding point, following the flow field in positive flow direction (down-gradient). Temporally, forward pathlines are by default started at the start time of the simulation, and drawn until the current time set in the Simulator toolbar. When stepping through the simulation time in upward direction, forward pathlines grow in length step by step. Temporal settings differing from the default can be chosen in the Properties panel.

• Backward: Applying the backward option, pathlines are started from the seeding points, following the flow field in negative flow direction (up- gradient). Temporally, backward pathlines are by default started at the current time set in the Simulator toolbar. Their travel time (negative) reaches back to the starting time of the simulation. Temporal settings differing from the default can be chosen in the Properties panel.