currently active set, instead of on individual objects or a range of them. For example:
(a) Choosing Lists > Cells from the menu bar and clicking the Show Cset Only option button will list only cells in the current set.
(b) When working with commands, typing VMOD,VSET,2.5
will modify the X-coordinate of every vertex in the current vertex set.
All set operations can also be performed by typing commands CSET, VSET, BSET, BLKSET, CPSET, SPLSET and DSET. These are described in detail in the
pro-STAR Commands volume.
Table Manipulation
pro-STAR tables are multi-variable entities akin to spreadsheets and can be used to store values for up to 100 dependent variables as functions of a combination of several independent variables. For most commonly used tables, the independent variables can be the three spatial coordinates, plus time for transient cases or iteration for steady-state cases. The dependent variables are normally flow field solution variables but, in principle, they could be anything of relevance to STAR-CD.
Basic functionality
At present, tables are used principally as a substitute for user subroutines in the following situations:
• Boundary Conditions — variable conditions along the surface of a boundary region; seeChapter 4, “Boundary Region Definition”, page4-7. For most boundary types, the independent variables may be any combination of spatial coordinates and, for transient cases, time. The only exception is outlet
boundaries where only time is allowed (i.e. there can be no spatial variation in outflow conditions along the outlet surface). The permissible dependent variables vary according to the boundary type considered; a full list is given under the various boundary type descriptions inChapter 4, or the
corresponding on-line Help topics for STAR GUIde’s“Define Boundary Regions” panel.
• Initial Conditions — non-uniform initial distributions of field variables; see Chapter 4, “Solution Domain Initialisation”. The independent variables may be any combination of spatial coordinates, for both steady and transient cases.
The permissible dependent variables for fluid materials are listed under topic
“Initialisation”. Scalar variables representing chemical species mass fractions may also be initialised, as described in a separate topic for scalar
“Initialisation”. Note that:
(a) The applicability of field variable and scalar initialisation tables can be restricted to a selected domain or a cell type
(b) The only dependent variable allowed for solid materials is temperature
• Source Terms — a description of mass, heat, momentum or scalar species sources; seeChapter 3, page3-8. The independent variables may be any
Table Manipulation
combination of spatial coordinates and time for transient cases, or iteration number for steady-state cases. The permissible dependent variables vary according to the source type considered; a full list is given in the on-line Help topics for the various sources definable via panel“Source Terms”. Note that, as with initial conditions, the applicability of source tables can be restricted to a selected domain or a cell type.
• Rotational Speeds — variable angular velocity in rotating systems, specified in panel“Rotating Reference Frames”. The independent variable is time for transient cases, or iteration number for steady-state cases. The dependent variable is angular velocity, expressed in r.p.m.
• Run Time Controls — variable time step for transient cases, specified in panel“Set Run Time Controls”. The independent variable is time, the dependent variable the time step size. Note that STAR assumes a linear variation in step size between the size values entered at two consecutive time points. This is illustrated by the example below, showing the desired time step variation and the table structure needed to achieve it:
Figure 2-1 Example of time step variation
Table 2-1: Time step size table
TIME DT
0.0 0.01
1.0 0.1
5.0 0.1
5.0 0.2
10.0 0.3
20.0 0.3
0.35 0.3 0.25
0.2 0.15 0.1 0.05 0.0
0.00 5.00 10.00 15.00 20.00
DT (sec)
Time (sec)
Table Manipulation
In addition, a special table type is used to enter problem data for Lagrangian Multi-Phase cases. The following two options are available in this category:
• Mass Flow Rate — injection rate history, specified in panel“Spray Injection with Atomization” which activates STAR-CD’s built-in spray modelling facilities. The table is used in transient analyses only and contains injector mass flow rates vs. time (see also topic“Define Injectors”). The same table type may also be used in panel“Injection Definition” as part of an explicit specification of injection characteristics.
• Diameter Distribution Function — a definition of the droplet diameter distribution function, in terms of spray percentage mass vs. droplet diameter.
This table may also be specified in panel“Injection Definition”.
The table editor
Table data are stored in text files and may be created or modified either via a suitable text editor or via pro-STAR’s own GUI facilities. Both options are accessed by clicking the special table editor button
at the bottom left-hand side of the main window. The basic functionality of the editor is described below.
New tables
To create a new table, click New Table to display the table view shown below:
Table Manipulation
Panel Data Entry
To use the dialog facilities directly, the following input is required (reading from left to right along the panel):
1. Table Title — enter a title up to 80 characters long, including spaces. Note, however, that only the first 30 characters found up to the first space in the string are usable by STAR.
2. Coordinate System — specify the coordinate system number to be used for spatial independent variables (see “Coordinate Systems” on page 2-8 of the Meshing User Guide). A search button is provided for choosing any of the currently defined systems from the Coordinate Systems dialog. Depending on your selection, the three space coordinates are interpreted as follows:
The coordinate names shown above inside parentheses should be used as table headers when creating a table outside this GUI environment.
3. Out of bound value options — prescribe the action to be taken if needing to calculate dependent variable values at points lying outside the table range.
Obviously, this does not apply to mass flow rate tables. The available options are:
(a) Error — issue an error message
(b) Extrapolate — use the closest two data points to calculate an extrapolated value
(c) Cutoff — use the closest data point as the variable value
4. Select Table Type — choose the basic table type from the list of options described under“Basic functionality”. The correct type is selected
automatically if you enter the editor indirectly, i.e. by clicking button New in a STAR GUIde panel that requires the use of tables.
5. Select Dependent Variables — for boundary and source tables, select also the specific type of boundary or source required from a secondary menu. All valid variables for the chosen table type are displayed automatically in the adjacent scroll list. To select an item from this list:
(a) For single items, click the desired variable
(b) For two or more items in sequence, click the first variable, press and hold down the Shift key, then click the last variable in the group
(c) For a random selection, hold down the Cntrl key and then click each variable in turn
6. Select Independent Variables — all valid variables for the chosen table type are displayed automatically as a series of option buttons. Choose those needed to define your table by clicking the corresponding button.
7. Click Setup to confirm your selections and enter the data input mode, as shown in the example below.
Cartesian Cylindrical Spherical Toroidal
Table Manipulation
The following points should be kept in mind when specifying table data:
• Table values should be entered for each dependent variable selected in step5 above. Your selection will be automatically reflected in the options shown on Dependent Variables scroll box. Fill in all required data for the currently selected variable before scrolling to the next one.
• The left-hand side of the panel will display a number of columns, one for each independent variable selected in step6 above. Fill each column with all the values assumed by that variable in the table, in ascending order.
• Tables containing two or more independent variables are essentially
multi-dimensional and need to be specified as a series of two-dimensional x-y tables, as in a spreadsheet. Accordingly, a pair of independent variable values are displayed as row and column headings and the user fills in appropriate values for the current dependent variable, as shown in the example above.
• To create such two-dimensional tables:
(a) Select the required pair from the Independent Variables menu, noting that pro-STAR activates only those combinations that correspond to the choice made in step6 above. The available pairs for the example shown (an X, Y, TIME selection) will be X - Y, X - TIME and Y - TIME and the pair chosen is X - Y.
(b) Fix the other independent variable(s) to a desired value, by clicking the radio button next to that value in its column on the left-hand side. In the example, TIME is fixed to 0.
Commands: TBDEFINE TBCLEAR TBWRITE TBGRAPH
Table Manipulation
(c) Click the FILL button. This sets up the 2D table and displays the chosen pair’s values as row and column headings
(d) Fill the table with the required dependent variable values and then click Save Data.
(e) Fix the other independent variable(s) to a different value and repeat steps (b) to(d) above as many times as necessary
(f) Select another pair from the Independent Variables menu and fill in another series of 2D tables. This might happen, for example, if instead of choosing to enter an X - Y set for a series of fixed TIME’s, you chose instead to enter X - TIME sets for fixed Y’s followed by Y - TIME sets for fixed X’s.
• Tables for rotational speeds, run-time controls and Lagrangian multi-phase specifications always have one independent variable and thus involve filling in a two-column table. The same also applies to the other tables if only a single independent variable is specified. A simplified display appears in the editor panel in these cases.
Once your data input is complete, you may:
1. Check the table contents graphically by plotting them as a pro-STAR graph (seeChapter 14 of the Post-Processing User Guide). To use this facility:
(a) Select the variable to be checked from the Dependent Variables scroll box. This will be plotted along the graph’s y-axis.
(b) Go to the graph setup section at the bottom of the panel (which now displays the chosen variable) and select an independent variable from the versus scroll box. This will be plotted along the graph’s x-axis.
(c) The names of the remaining independent variable(s) will also be
displayed in the const boxes. For the purposes of the graph, these will be fixed to the value indicated by the radio button in each variable’s column.
These values will also appear inside the @ boxes.
(d) Click Graph to see the result of your selection.
2. Save your data in a table file. The file name should have extension .tbl and should be entered in the File Name box at the bottom of the panel.
pro-STAR’s built-in browser may also be used to locate an existing file. Click Write Table to save your data in this file.
File Data Entry
An alternative method of generating a new table is to import existing tabular data from an ASCII file created outside pro-STAR. To use this method:
1. After opening the Table Editor dialog, select the Import button situated under the New Table option. This will display the alternative panel view shown below.
Table Manipulation
2. Click Instruction to open a special text panel giving detailed information on how the user file shoud be structured and formatted. Check that your own file conforms to this standard and modify if necessary.
3. Enter the name of your file in the ASCII Data File Name box, or use pro-STAR’s built-in file browser to help locate it.
4. Select option space or comma from the Delimiter menu to indicate how the numerical values in your table are separated from each other.
5. Click Import to import your data into pro-STAR.
6. Enter the remaining table specification items on the right-hand side of the panel, as described on page2-27.
7. Check the table contents graphically, if required, and then save them in a pro-STAR table file, as described on page2-29.
Existing table display/modification
To read and display the contents of an existing table, click Read Table at the top left-hand side of the editor and then enter the file name (of form case.tbl) in the File Name box. pro-STAR’s built-in browser may be used to help locate the file.
Once the table has been read, its contents can be checked visually using the graph function described in the previous section or modified as required. Note that:
1. You cannot add new dependent or independent variables to an existing table (or delete any that are currently defined)
Commands: TBREAD TBLIST TBMODIFY TBGRAPH