FEFLOW Time Series

A time series consists of a unique ID and an arbitrary number of (time, value) data pairs. Optionally, a name can be specified for each time series. The time intervals do not have to be equal. When defining time series, it should be considered that automatic time-stepping procedures make sure to meet each time value with a time step, so that short-interval time series may lead to higher numbers of calculation time steps. Interpolation between the data pairs can be defined as linear, constant (step function) or Akima/Aki­ma2.

Time series can be imported from the so-called FEFLOW Power Functions File (*.pow) or directly be defined and edited in the Time-Series dialog that is opened via the Edit menu. A third option is to paste tabular data copied from, e.g., Microsoft Excel/Access or a text editor, directly into a time series in the editor from the clipboard.

 

Time-series editor.

Time series can be applied to the model cyclically, i.e., a time series defined for part of the simulation time is applied repeatedly until the end of the simula­tion, or they can be used in linear mode. If the time series only covers a part of the simulation time in linear mode, the first value is used from the simula­tion start to the beginning of the time-series definition, and the last value in the series is applied until the end of the simulation.

Time series can also contain gaps to turn a boundary condition off during spe­cific time intervals or to limit the application of a boundary condition to a cer­tain time period. Gaps at the beginning and end of a time series can be used to make sure that the time-series values are not applied before the first and after the last defined time-series step as described above for the linear time mode.

Units for Time Series

By default, time series do not contain any information on the units of the time/value pairs and FEFLOW will use the internal unit of a specific parame­ter for the assignment of the time-series data, e.g., [m³/d] for well boundary conditions and [m] for a hydraulic-head boundary condition. It is however possible to define the unit class and user unit for editing the data of a time series. While the unit class for the Time data is always time, a time series may contain values of pumping rates, hydraulic head or concentration. Selecting a user unit for Value therefore requires prior definition of the appro­priate unit class (e.g., pumping rate, length, concentration).