Streamline and Pathline Traces:
A particle trace represents the path a particle would take if released in a flow field. From an initial seed point (the emitter), a path is formed by integrating through the velocity field over time. The path is therefore everywhere parallel to the flow. For models with rotational periodic geometry, streamlines and pathlines can exit a symmetry face and re-enter the corresponding symmetry face and continue. Traces calculated using a single time step in a flow field are called streamlines. The path calculated using a transient flowfield that is updated as the calculation proceeds is known as a pathline.
EnSight provides a great deal of control over emitter definition and trace appearance:
Emitters can be defined using one of the built-in tools (Cursor, Line, or Plane) or by clicking on any surface in the Graphics Window. The nodes of an arbitrary part can be used as an emitter, or the emitter time and locations can be read from a file (see EnSight Particle Emitter File Format).
The streamline path can be generated in the positive, negative, or positive and negative time directions.
Traces can be restricted to lie on any surface to search for flow topology and separation features.
For transient cases, an emitter can have a delta time that controls the periodic release of additional particles into the dynamic flow.
Emitters can be interactive; as you move the emitter with the mouse, the associated traces automatically recalculate and redisplay. (This option is not available for surface-restricted Particle traces, traces emitted from a Part, in Server of Server mode, or for Pathlines.)
Trace paths can be displayed as lines, ribbons, tubes, or as square tubes, where ribbon or tube twist follows the local flow rotation around the path.
Right-click on an individual trace and select Hide this trace emission to hide it and select Show all trace emissions to reset the traces to visible. This is useful for making uninteresting traces invisible while retaining the interesting ones.
If the particle trace part is colored by a constant color: then the following options are available:
Right-click and select Set trace emission to random colors to assign a random color automatically to each emission of the particle trace part. This is useful for distinguishing between traces.
Right click an individual trace and select Set trace emission to constant color... to assign a color to the individual emission selected. The standard color widget will appear to allow you to select a color.
To reset the color of the trace colors back to a uniform color, simply color the traces by a constant.
Particle traces can be easily animated to provide intuitive comprehension of the flow field. Complete control over all aspects of the animating tracers is provided, including length, speed, and release interval for multiple pulses.
Another form of trace that is available in EnSight is entitled node tracking. This trace is constructed by connecting the locations of nodes through time. It is useful for changing geometry or transient displacement models (including measured particles) which have node ids.
A further type of trace that is available is a min or max variable track. This trace is constructed by connecting the min or max of a chosen variable (for the selected parts) though time. Thus, on transient models one can follow where the min or max variable location occurs.
Both the node tracking and the min/max variable tracking options are like a connect-the-dots through time trace.