Time-Line Of Computational Time Steps Defined Using the Variable Time Step Option and the XY Series Editor.
The Time Control dialog is used to enter the data used by FEMWATER to compute the computational time intervals. It is also used to define the reference time. The options in the dialog are as follows:
There are two methods for defining the computational time steps: Constant time step and Variable time step. With the Constant time step method, the first time step is assumed to begin at time 0.0. A constant interval time is entered along with a maximum simulation time. For example, if a constant time step of 2.0 is defined along with a maximum simulation time of 10.0, six computational time steps will be defined at 0.0 (the initial condition), 2.0, 4.0, 6.0, 8.0 and 10.0.
The Variable time step option permits variable intervals between time steps. Selecting the Variable Times button brings up the XY Series Editor. The XY Series Editor has one column for entering times and another for entering time steps. In the time column, the absolute time for a computational time step should be entered. The time step corresponding to each time represents the interval to be used from one specified time to the next.
A simple example of times and time steps defined in the XY Series Editor and the resulting computational time steps to be used by FEMWATER is shown below. In this case the maximum simulation time is equal to 48.0.
Time-Line Of Computational Time Steps Defined Using the Variable Time Step
Option and the XY Series Editor.
The options at the bottom of the Time Control dialog are used to enter the reference time for the FEMWATER simulation. The reference time is the date/time corresponding to the beginning of the simulation (t=0). If a reference time is entered and the Date/Time option is selected in the Time display section, all time values entered for transient input data (i.e., time series defined in the XY Series Editor) can be entered in a date/time format rather than a scalar time format. Also, when post-processing, the values shown in the time step selector in the Data Browser or at the top of the GMS Window are displayed in the date/time format. Furthermore, any time series curves entered as part of the FEMWATER conceptual model in the Map module that were defined using the date/time format will be automatically converted to the proper time scale when the conceptual model is converted to mesh-based numerical model.
Related Links:
FEMWATER Interface
Model Input