Examining Plots

We have already examined the velocity plot and seen that the numerical solution compares well with experimental data. Now, given that the y+ contours indicate that the wall data are also reasonably accurate, we can estimate the length of the recirculation zone from the wall shear stress plot:

Select the WSS Plot tab at the top of the Display window.

Recirculation zones occur upstream and downstream of the obstacle. These are visible on the graph as regions where the wall shear stress is negative. To determine the length of the downstream recirculation zone we will change the graph formatting:

Select the Plots > WSS Plot > Y Types > Y Type 1 > Y = 0 > Line Style node.

In the Properties window, change the Style property to Solid.

Select the Symbol Style node.

Change the Shape property to None.

Select the Plots > WSS Plot > Axes > X Axis > Labels node.

Change the Maximum and Minimum properties to 0.9 and 0.3, respectively.

Change the Label Spacing property to 0.05.

Select the Labels node within the Y Axis node.

Change the Maximum and Minimum properties to 0.005 and -0.005, respectively.

Change the Label Spacing property to 0.005.

The above result shows that the downstream recirculation zone extends from approximately X = 0.38 m to X = 0.825 m and hence is roughly 0.445 m in length.