29.9.9 Modifying Axis Attributes

You can modify the appearance of the XY and histogram plot axes by changing the parameters that control the labels, scale, range, numbers, and major and minor rules. For each type of plot (solution XY, file XY, profile, residual, histogram, etc.), you can set different axis parameters in the Axes dialog box (Figure  29.9.13). Note that the title following Axes in the dialog box indicates which plot environment you are changing (e.g., the Axes - Solution XY Plot dialog box controls axis parameters for solution XY plots).

Figure 29.9.13: The Axes Dialog Box

To open the Axes dialog box for a particular plot type, click the Axes... button in the appropriate dialog box (e.g., the Solution XY Plot, File XY Plot, Plot Profile Data, Plot Interpolated Data, or Residual Monitors dialog box).

Using the Axes Dialog Box

The Axes dialog box allows you to independently control the characteristics of the ordinate ( $y$ axis) and abscissa ( $x$ axis) on an XY plot or histogram. To set parameters for one axis or the other, you will follow the procedure below:

1.   Choose the axis for which you want to modify the attributes by selecting X or Y under Axis.

2.   Set the desired parameters.

3.   Click Apply and then choose the other axis and repeat the steps, if desired.

Your changes to the axis attributes will appear in the graphics window the next time you generate a plot.

Changing the Axis Label

If you want to modify the label for the axis, you can do so by editing the Label text field in the Axes dialog box.

Changing the Format of the Data Labels

You can change the format of the labels that define the primary data divisions on the axes using the controls under the Number Format heading in the Axes dialog box.

• To display the real value with an integral and fractional part (e.g., 1.0000), select float in the Type drop-down list. You can set the number of digits in the fractional part by changing the value of Precision.

• To display the real value with a mantissa and exponent (e.g., 1.0e-02), select exponential in the Type drop-down list. You can define the number of digits in the fractional part of the mantissa in the Precision field.

• To display the real value with either float or exponential form, depending on the size of the number and the defined Precision, choose general in the Type drop-down list.

Choosing Logarithmic or Decimal Scaling

By default, decimal scaling is used for both axes (except for the $y$ axis in residual plots, which uses a log scale). If you want to change to a logarithmic scale, turn on the Log option in the Axes dialog box. To return to a decimal scale, turn off the Log option. Note that when you are using the logarithmic scale, the Range values are the exponents; to specify a logarithmic range from 1 to 10000, for example, you will specify a minimum value of 1 and a maximum value of 4.

Resetting the Range of the Axis

By default, the extents of the axis will range from the minimum value plotted to the maximum value plotted. If you want to change the range or extents of the axis, you can do so by turning off the Auto Range option in the Axes dialog box and setting the new Minimum and Maximum values for the Range. This feature is useful when you are generating a series of plots and you want the extents of one or both of the axes to be the same, even if the range of plotted values differs. (For example, if you are generating plots of temperature on several different wall zones, you might want the minimum and maximum temperature on the $y$ axis to be the same in every plot so that you can easily compare one plot with another. You would determine a temperature range that includes the temperatures on all walls, and use that as the range for the $y$ axis in each plot.)

Controlling the Major and Minor Rules

ANSYS FLUENT allows you to display major and/or minor rules on the axes. Major and minor rules are the horizontal or vertical lines that mark, respectively, the primary and secondary data divisions and span the whole plot window to produce a "mesh.'' To add major or minor rules to the plot, turn on the Major Rules or Minor Rules option. You can then specify a color and weight for each type of rule. Under the Major Rules or Minor Rules heading, select the desired color for the lines in the Color drop-down list and specify the line thickness in the Weight field. A line of weight 1.0 is normally 1 pixel wide. A weight of 2.0 would make the line twice as thick (i.e., 2 pixels wide).