Step 9: Displaying the Preliminary Solution

  In the steps that follow, you will visualize various aspects of the flow for the preliminary solution, using the task pages listed under the Results heading in the navigation pane.

1.   Display filled contours of velocity magnitude on the symmetry plane (Figure  1.5).

Graphics and Animations Contours Set Up...

(a)   Enable Filled in the Options group box.

(b)   Make sure that Node Values is enabled in the Options group box.

(c)   Select Velocity... and Velocity Magnitude from the Contours of drop-down lists.

(d)   Select symmetry from the Surfaces selection list.

(e)   Click Display to display the contours in the active graphics window.

Extra:   When you probe a point in the displayed domain with the mouse, the level of the corresponding contour is highlighted in the colormap in the graphics window, and is also reported in the console.

Figure 1.5: Predicted Velocity Distribution after the Initial Calculation

2.   Display filled contours of temperature on the symmetry plane (Figure  1.6).

Graphics and Animations Contours Set Up...

(a)   Select Temperature... and Static Temperature from the Contours of drop-down lists.

(b)   Click Display and close the Contours dialog box.

Figure 1.6: Predicted Temperature Distribution after the Initial Calculation

3.   Display velocity vectors on the symmetry plane (Figures  1.7 and 1.8).

Graphics and Animations Vectors Set Up...

(a)   Select symmetry from the Surfaces selection list.

(b)   Click Display to plot the velocity vectors.

Note:   The Auto Scale option is enabled by default in the Options group box. This scaling sometimes creates vectors that are too small or too large in the majority of the domain. You can improve the clarity by adjusting the Scale and Skip settings, thereby changing the size and number of the vectors when they are displayed.

(c)   Enter 4 for Scale.

(d)   Set Skip to 2.

(e)   Click Display again to redisplay the vectors (Figure  1.7).

Figure 1.7: Resized Velocity Vectors

(f)   Close the Vectors dialog box.

(g)   Zoom in on the vectors in the display.

  To zoom in, refer to Table  1.1. The image will be redisplayed at a higher magnification (Figure  1.8).

Figure 1.8: Magnified View of Velocity Vectors

(h)   Zoom out to the original view.

   To zoom out or translate the view refer Table  1.1. The image will be redisplayed at a lower magnification (Figure  1.7).

You also have the option of selecting the original view in the Views dialog box: select front from the Views selection list and click Apply.

Graphics and Animations Views...

4.   Create a line surface at the centerline of the outlet.

Surface $\rightarrow$ Iso-Surface...

(a)   Select Mesh... and Z-Coordinate from the Surface of Constant drop-down lists.

(b)   Click Compute.

  The range of values in the $z$ direction will be displayed in the Min and Max boxes.

(c)   Retain the default value of 0  ${\rm inches}$ for Iso-Values.

(d)   Select pressure-outlet-7 from the From Surface selection list.

(e)   Enter z=0_outlet for New Surface Name.

(f)   Click Create.

  After the line surface z=0_outlet is created, a new entry will automatically be generated for New Surface Name, in case you would like to create another surface.

(g)   Close the Iso-Surface dialog box.

5.   Display and save an XY plot of the temperature profile across the centerline of the outlet for the initial solution (Figure  1.9).

Plots XY Plot Set Up...

(a)   Select Temperature... and Static Temperature from the Y Axis Function drop-down lists.

(b)   Select z=0_outlet from the Surfaces selection list.

(c)   Click Plot.

(d)   Enable Write to File in the Options group box.

  The button that was originally labeled Plot will change to Write....

(e)   Click Write... to open the Select File dialog box.

i.   Enter outlet_temp1.xy for XY File.

ii.   Click OK to save the temperature data and close the Select File dialog box.

(f)   Close the Solution XY Plot dialog box.

Figure 1.9: Outlet Temperature Profile for the Initial Solution

6.   Define a custom field function for the dynamic head formula ( $\rho \vert V\vert^2/2$).

Define $\rightarrow$ Custom Field Functions...

(a)   Select Density... and Density from the Field Functions drop-down lists, and click the Select button to add density to the Definition field.

(b)   Click the X button to add the multiplication symbol to the Definition field.

(c)   Select Velocity... and Velocity Magnitude from the Field Functions drop-down lists, and click the Select button to add $\vert$V $\vert$ to the Definition field.

(d)   Click y ^ x to raise the last entry in the Definition field to a power, and click 2 for the power.

(e)   Click the / button to add the division symbol to the Definition field, and then click 2.

(f)   Enter dynamic-head for New Function Name.

(g)   Click Define and close the Custom Field Function Calculator dialog box.

7.   Display filled contours of the custom field function (Figure  1.10).

Graphics and Animations Contours Set Up...

(a)   Select Custom Field Functions... and dynamic-head from the Contours of drop-down lists.

Hint:    Custom Field Functions... is at the top of the upper Contours of drop-down list. After you have opened the drop-down list, scroll up by clicking the up-arrow button on the scroll bar on the right.

(b)   Make sure that symmetry is selected from the Surfaces selection list.

(c)   Click Display and close the Contours dialog box.

Figure 1.10: Contours of the Dynamic Head Custom Field Function

Note:   You may need to change the view by zooming out after the last vector display, if you have not already done so.

8.   Save the settings for the custom field function by writing the case and data files ( elbow1.cas.gz and elbow1.dat.gz).

File $\rightarrow$ Write $\rightarrow$ Case & Data...

(a)   Ensure that elbow1.cas.gz is entered for Case/Data File.

Note:   When you write the case and data file at the same time, it does not matter whether you specify the file name with a .cas or .dat extension, as both will be saved.

(b)   Click OK to save the files and close the Select File dialog box.