Unsteady Flow Time settings are important for both Unsteady Flow and Field Line Advection
- Seed time start, end, increment: When a rake is used to specify seed points, these three integers are used to specify one or more time steps that will result in flow lines being started. Seed points are used to start flow integration at the seed time start, and repeatedly at intervals specified by the time step increment, until the end is reached. Note that these three integers must be positive. When using a seed list, a seed is introduced at a time step if that time step is indicated in the seed list and if the time step occurs in the sequence determined by these three parameters.
- Timestep sample start, end, increment: These determine a sequence of time steps for which the data will be sampled. Normally this will include all the time steps in the VDC, but it can also be set to only use a subset of those time steps, for a coarser time integration. When the integration is forward, the first time step sample should be at the first time step for which there are seed points. When the integration is backward, the last time sample should be at the last time step for which there are seed points.
- The time step list is an alternative to using Timestep sample start, end, increment. Users may specify an arbitrary set of timesteps to be used for unsteady integration, by inserting them into this table, by use of the "Add", "Delete", and "Rebuild" buttons.
- Unsteady samples per time step indicates how many points will be shown along a flow line. This does not affect the flow integration. If this value is 1.0, then the flow display will include one line, arrow, or point at each time step. A larger value results in more samples along the flow line.
- Timestep display interval min, max determines an interval of the flow line that will be displayed at each time step. By default this is set to -100 and 1, indicating that, at each time step T, a flow line will be displayed from T-100 to T+1, thereby displaying up to 100 of the past positions of the point and 1 position in the future.
