23.7.3 Step-by-Step Reporting of Trajectories

At times, you may want to obtain a detailed, step-by-step report of the particle trajectory/trajectories. Such reports can be obtained in alphanumeric format. This capability allows you to monitor the particle position, velocity, temperature, or diameter as the trajectory proceeds.

The procedure for generating files containing step-by-step reports is listed below:

1.   Follow steps 1 and 2 in Section  23.7.1 for displaying trajectories. You may want to track only one particle at a time, using the Track Single Particle Stream option.

2.   Select Step by Step as the Report Type.

This option is only available for steady-state cases. For transient cases, see Section  23.7.4.

3.   Select File as the Report to option. (The Display button will become the Write... button.)

4.   In the Significant Figures field, enter the number of significant figures to be used in the step-by-step report.

5.   Click the Reporting Variables... button. The Reporting Variables dialog box will appear (Figure  23.7.3), where you can change the variables in the report. The list under Variables in Report contains all variables currently reported. The Remove button removes selected variables from that list. The Default Variables button restores the default list. The list under Particle Variables contains the particle variables that are available for you to select. You can add selections to the report using the Add Variable button. Clicking the Add Color by button adds the Color by variable to the list of Variables in Report, which is the only way to get cell values or customized field functions into the report.

Note that it is possible to select one variable in the Reporting Variables dialog box and a variable from the Color by drop-down list in the Particle Tracks dialog box, however, each variable is reported only once.

Figure 23.7.3: The Reporting Variables Dialog Box

6.   Click the Write... button and specify a file name for the step-by-step report file in the resulting Select File dialog box (see Section  2.1.6).

A detailed report similar to the following example will be saved to the specified file before the trajectories are plotted. (You may also choose to print the report in the console by choosing Console as the Report to option and clicking Display or Track, but the report is very long that it is unlikely to be of use to you in that form.)

FILE TYPE:	1
COLUMNS: 12
TITLE:  TRACK HISTORY

 COLUMN    TYPE    VARIABLE                         (UNITS)
 ------    ----    --------                         ------
      1       2    TIME                             (SECONDS)
      2      10    X-POSITION                       (METERS)
      3      10    Y-POSITION                       (METERS)
      4      10    Z-POSITION                       (METERS)
      5      10    U-VELOCITY                       (M/SEC)
      6      10    V-VELOCITY                       (M/SEC)
      7      10    W-VELOCITY                       (M/SEC)
      8      10    DIAMETER                         (METERS)
      9      10    TEMPERATURE                      (KELVIN)
     10      10    DENSITY                          (KG/M3)
     11      10    MASS                             (KG)
     12      10    NUMBER                            - 
---------------------------------------------

0.00000e+00   5.00000e-02   5.00000e-02   5.00000e-02   2.00000e+01   0.0000 . . .
1.07087e-07   5.00000e-02   5.00000e-02   5.00000e-02   1.23339e+01   2.6696 . . .
2.51617e-07   5.00000e-02   5.00000e-02   5.00000e-02   1.04417e+01   3.3286 . . .
 .             .             .             .             .
 .             .             .             .             .
 .             .             .             .             .

The default step-by-step report lists the position, velocity, diameter, temperature, density and mass of the particle at selected time steps along the trajectory. In addition, the variable you have selected in the Color by list is also included. If you choose Console as the Report to option, the variable names are written as the header of each column. (You may need to use the scroll bar to view all variables in this column.)

Time      X-Position Y-Position Z-Position X-Velocity Y-Velocity Z-Veloc 
0.000e+00  1.000e-03  3.120e-02  0.000e+00  1.000e+01  5.000e+00  0.000e
1.672e-05  1.168e-03  3.128e-02  0.000e+00  1.010e+01  4.988e+00  0.000e
3.342e-05  1.337e-03  3.137e-02  0.000e+00  1.019e+01  4.977e+00  0.000e
5.010e-05  1.508e-03  3.145e-02  0.000e+00  1.028e+01  4.965e+00  0.000e
6.675e-05  1.680e-03  3.153e-02  0.000e+00  1.038e+01  4.954e+00  0.000e
8.338e-05  1.854e-03  3.161e-02  0.000e+00  1.047e+01  4.942e+00  0.000e
     .          .          .          .          .          .          .
     .          .          .          .          .          .          .
     .          .          .          .          .          .          .

If you change the reporting variables, only those selected will appear in the report. The particle time is always reported in the first column. Note that it is possible to select one variable in the Reporting Variables dialog box and a variable from the Color by drop-down list in the Particle Tracks dialog box, however, each variable is reported only once.

When the report is written to a file, a table at the beginning of the file lists all variables selected with the corresponding unit. Thus you can display or export any variable along a particle trajectory to the console or to a file.

Note that the Coarsen option affects the step-by-step report.