Numerical Results

Mach Number Contours

The following video shows how to make a plot of the Mach number contours using CFD-Post. If the videos below don't appear in your browser, try reloading the webpage.

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Summary of the above video:

1. Some calculated parameters are not by default carried over into CFD-Post. We are interested in such quantities (i.e. Mach Number). To manually transfer a customized selection of quantities:
   1. Click File > Data File Quantities...
   2. Under Additional Quantities, select Static Pressure, Total Pressure, Mach Number, and Total Temperature.
2. Post-processing will be done in CFD-Post. To open, double-click Results in Workbench.
3. We are interested in viewing contours of Mach Number in CFD-Post
   1. Select Insert > Contour > Name > Mach No. 
   2. Under Details of Mach No, select Locations > symmetry 1.  
      1. Variable > Mach Number > No Contours = 101
4. Turn on the mesh in the graphics pane
   1. Check the box next to symmetry 1 in the Outline tree > Click Render > Show Mesh Lines.
5. Turn off the mesh by deselecting symmetry 1 in the outline tree
6. Save a copy of the figure in the graphics pane
   1. Select the camera icon in the toolbar.

Pressure Contours

The following video shows how to make a plot of the pressure contours.

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Summary of the above video:

1. Turn off the Mach Number contours in the graphics window
   1. Uncheck the box next to Mach no in the Outline tree.
2. We are interested in viewing contours of pressure in CFD-Post
   1. Select Insert > Contour
   2. Name > Pressure Contours
   3. Under Details of Pressure contours, select Locations > symmetry 1.  
      1. Variable > Pressure.
3. To increase the number of contours to 101
   1. Under Details of Pressure contours, scroll down to # of Contours. Type “101”.

Velocity Vectors

To plot the velocity vectors, follow the steps in the video below.

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Summary of the above video:

1. We are interested in viewing velocity vectors in CFD-Post.
   1. Select Insert > Vector
   2. Type “Velocity vectors” under Name in the Insert Vector dialogue box that appears.
   3. Under Details of Velocity vectors, select Locations > symmetry 1.  
2. To make the velocity vectors more visible, turn off the pressure contours
   1. Uncheck the box next to Pressure contours in the Outline tree

Plot Mach Number Variation Along y=0.4 m

First, we'll create a line at y=0.4m. Then, we'll plot the Mach number variation along this line using the "Chart" facility in CFD-Post. These steps are shown in the video below. Note that you can export the data to a csv file using the Export button next to Apply in the Chart menu. You can then open the csv file in Excel to determine the values of Mach number, pressure etc. behind the shock to, say, 4 significant digits. 

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Summary of the above video:

1. Insert line y = 0.4 m in CFD-Post.
   1. Select Location > Line > Name Line 1
   2. Under Details of Velocity vectors, type Point 1 coordinates (0,0.4,0) and Point 2 coordinates (1.5,0.4,0).
2. Plot Mach Number along the newly created line y = 0.4 m
   1. Select Insert > Chart
   2. Type “Mach no along Line 1” under Name 
   3. Under Details of Mach no along Line 1, select the Data Series tab. Select Location > Line 1.  
      1. select the X Axis tab. Select Variable > X.
      2. select the Y Axis tab. Select Variable > Mach Number.
3. To increase the number of samples along line y = 0.4 m to 100.
   1. Double click on Line 1 in the Outline tree.
   2. Under Details of Line 1, type “100” in Samples.

Go to Step 7: Verification & Validation

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Results

Velocity Vectors

First, let's take a look at the velocity vectors. In the Outline window, under Results select Colors and Animations. In the Colors and Animations window, under Graphics, select Vectors. Then press Set Up....

In the Vectors window that opens, change the Scale of the arrows to 0.25, and change the Color by parameter to Velocity... Mach Number

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Hit Display to view the vectors in the graphics window

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Once you have plotted the velocity vectors, you may close the Vectors menu.

Mach Number Contours

Next, we will plot the contours of mach number. In the Graphics and Animations window under _Graphics, select Contours, and press Set Up.... Change the Contours Of parameter to Velocity... Mach Number. Next, check the box next to Filled.

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Change the Levels to 50 and press Display

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Pressure Coefficient Contours

Now, change the Contours Of parameter to Pressure... Pressure Coefficient and press Display.

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When you have plotted the contours, you may close the Contours window.

Pressure Coefficient Along Wedge

In the Outline window under Results, select Plots. In the Plots window, select XY plot and press Set Up.... Change the Y Axis Function to Pressure... Pressure Coefficient, and select the Wedge under Surfaces.

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To see the plot, press Plot

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