SUTRA Time Controls Dialog Box

The SUTRA Time Controls dialog box is used to define the time schedules in a SUTRA model and a few other time-related options. The SUTRA Time Controls dialog box is displayed by selecting Model|SUTRA Time Controls...

SUTRA uses "schedules" to control the time steps in the model as well as observation times and changes in boundary conditions. There are four types of schedules: "time list," "time cycle," "step list," and "step cycle."

A "time list" is a list of times. A "time cycle" defines an initial time and a time increment and a final time to define time steps. There are also other controls to allow the increment to grow and to limit the total number of times. A "step list" lists time step numbers. A "step cycle" is similar to a "time cycle" except that time step numbers are used instead of times.

The very first schedule must be named "TIME_STEPS" and must be either a "time list," "time cycle."

The SUTRA Time Controls dialog box has two tabs: Schedules and Options.

The Schedules tab has a list of schedules on the left. The main section of the Schedules tab displays the parameters that define a particular schedule. Selecting a schedule in the list will cause its parameters to be displayed in the main section of the Schedules tab.

In addition to time schedules defined here, ModelMuse allows "custom" schedules to be defined for observations and boundaries. Custom time schedules may include times that are not listed in the TIME_STEPS schedule displayed in the SUTRA Time Controls dialog box. When generating the SUTRA input file, ModelMuse will merge any times in custom time schedules into the TIME_STEPS schedule and make any other required changes to "step list" or "step cycle" schedules. Such changes may include converting a "step cycle" schedule to another type of schedule.

Each schedule must have a name and schedule type. These are specified in the Schedule name (SCHNAM)and Type of time step schedule (SCHTYP) controls. For "time list" and "time cycle" schedules, the user must also specify whether the times represent absolute or elapsed time. The user makes this choice with the group of radio buttons labeled Manner of time specification (CREFT). For "time list" and "time cycle" schedules, there is also a Scale factor for times (SCALT) that is applied to all time values in the schedule.

The remainder of the controls vary depending on SCHTYP. For "time list" and "step list" schedules, there is a table in which times or time steps respectively can be entered. For each table there is a control for the Number of lines in the table and three buttons for adding , inserting , or deleting rows from the table.

 

For "time cycle" schedules, the user must define the following.

NTMAX is the maximum number of times in the schedule not including the initial time.

TIMEI is the initial time for the schedule.

TIMEL is the limiting time - the largest time that can be include in the schedule.

TIMEC is the initial time increment.

NTCYC is the number of cycles after which the time increment is updated. The current time increment is multiplied by TCMULT (see below) after every NTCYC cycles. (The value of the time increment is limited by TCMIN and TCMAX; see below.)

TCMULT is the factor by which the time increment is multiplied after every NTCYC cycles.

TCMIN is the minimum time increment allowed.

TCMAX is the maximum time increment allowed.

 

For "step cycle" schedules, the user must define the following.

NSMAX is the maximum number of time steps in the schedule not including the initial time.

ISTEPI is the initial time step for the schedule.

ISTEPL is the limiting time step - the largest time that can be include in the schedule.

ISTEPC is the time step increment.

 

On the Options tab, the user defines the following.

TICS is the time at which the initial conditions are specified (in seconds).

NPCYC is the number of steps in the pressure solution cycle. Pressure is solved on time steps numbered: n(NPCYC), where n is a positive integer, as well as on initial time step.

NUCYC is the number of steps in the transport solution cycle. The transport equation is solved on time steps numbered: n(NUCYC), where n is a positive integer, as well as on initial time step.

SUTRA requires that either NPCYC or NUCYC be one.

The Time Units Converter dialog box can be used to convert values specified in a unit different from that used in the model to values in the time units specified in the model. Click the Convert time units button to display the Time Units Converter dialog box.