1D linear interpolation along lines

I have to simulate a flood wave along a river. I use the flow transfer BC and 1D linear interpolation along lines, using the axis of the river and a shape file of the points with time series. I need clarification on temporal interpolation. What means "feflow can also interpolate between the time stages to consider the translation of a flood wave"?

from the help: "In case of interpolating between time series (time-varying link type) FEFLOW can interpolate values at the time stages of the time series, or it can also interpolate between the time stages, e.g., to consider the translation of a flood wave between two locations along a river."

So, if you set up a link to a database file that contains time series data for each xy location, then feflow will set up power functions (time series) for each boundary condition it sets at a node.  Often a model will have fewer points in a time series than time steps, so feflow can also be set up to also linearly interpolate the boundary condition value at a time step that falls between to points in the boundary condition's time series.

Pete

Here I give you an example about the difference between the [b]interpolation at current stages[/b] and the [b]interpolation of additional time stages[/b].

Let’s assume two gauges along a river. One gauge is located upstream and the other gauge is located further downstream. The upstream gauge measures a flood wave [b]Curve 1[/b] and the river gauge located downstream measures the flood wave [b]Curve 2[/b]. Please note the following attached file to see both curves: [i]Curve1_Curve2.jpg[/i].

If you interpolate between these two hydrographs spatially only, you get a curve which is characterized by two separated flood waves. Please see the attached file [i]interpolation_at_current_stages.jpg[/i]

In contrast, if you take “transient effects” into account you consider the flood wave dampening effect by retention. Please see the attached file [i]interpolation_of_additional_time_stages.jpg[/i]

Of course, both methods solely interpolate mathematically without taking real physical process into account. However, if you [b]interpolate additional time stages[/b] you mimic retention effects in your interpolation as indicated by a single damped flood wave curve.

Attached please find also the two files I was mentioning in my previous post:

[i]interpolation_at_current_stages.jpg[/i]
[i]interpolation_of_additional_time_stages.jpg[/i]