Plotting Velocity Vectors

Select the Vector Scene 1 > Displayers > Vector 1 > Parts node.

In the Properties window, click on the right half of the Parts property to display the Select Objects dialog

Select the Fluid: inlet, Fluid: inlet2, Fluid: outlet and Fluid: wall parts and then click Close

Select the Vector Field node and, in the Properties window, select Cell Relative Velocity from the Function pop-up menu to display velocities in the pipe's interior

After some rotation and repositioning of the mesh, the results should appear as shown below.

Note that the flow field pattern cannot be seen very clearly because the above plot includes far too many vectors. To thin out the vectors and generally improve the clarity of the plot

Select node Vector 1 then, in the Properties window, change the value of the On Ratio property to 7

The revised plot will now clearly show the flow swirling through the mixing pipe.

Click on the Save-Restore button in the toolbar,

, and select Store Current View.

Next, plot velocity vectors in the plane that was previously used for the velocity magnitude contour plot.

Right-click on the Scenes node and select New Scene > Vector

Select the Vector Scene 2 > Displayers > Vector 1 > Parts node and, in the Properties window, click on the right half of the Parts property to display the Select Objects dialog

Select the plane section 2 part and then click Close

Click on the Save-Restore button in the toolbar and select Restore View > View 1 to produce the cross-sectional velocity display shown below.

The vectors shown above are too widely spaced at the center of the pipe. However, this is not the case near the walls where the presence of a finer mesh results in more vectors being displayed.

A plot with evenly distributed vectors across the plane can be achieved using the Presentation Grid facility.

Right-click the Derived Parts node and select option New Part > Presentation Grid

A new interactive in-place dialog (Create Presentation Grid) appears on the left of the Graphics window enabling you to define the desired plane.

In the Create Presentation Grid dialog, click Input Parts and then select Fluid from the corresponding Select Object dialog

Specify the grid spacing in the X and Y directions by entering 50 in the X/Y Resolution boxes, as shown below.

Click Plane Tool to define the presentation grid plane graphically using the mouse, as shown below. The Create Presentation Grid dialog can be hidden using the arrow button located at the bottom-left corner

Adjust the position and orientation of the grid so that it and the plane section are approximately coplanar.

Click Create in the Create Presentation Grid dialog

Note that a new node, presentation grid, will now appear as an additional Derived Parts constituent. A second node, Presentation Grid Geometry 1, will also appear under the Displayers node belonging to Vector Scene 2.

Click Close

Select the Parts node in the Vector 1 displayer node of Vector Scene 2

In the Properties window, click on the right half of the Parts property and then select the presentation grid part

Deselect the plane section 2 part, then click Close.

Select the displayer node Presentation Grid Geometry 1

In the Properties window, clear the Surface checkbox to produce a plot similar to the one shown below.