Figure 24.10: Run Adjoint Calculation Dialog Box

a.Click the Initialize button. This initializes the adjoint solution everywhere in the problem domain to zero.

b.Set the Number of Iterations to 200. The adjoint solver is fully configured to start running for this problem.

c.Click the Calculate button to advance the solver to convergence.

Figure 24.11: Residuals for the Converged Solution

d. When the calculation is complete, Close the Run Adjoint Calculation dialog box.

24.4.4. Step 4: Postprocess and Export Drag Sensitivity

In this section, postprocessing options for the adjoint solution are presented.

vk.com/club152685050Using the Adjoint Solver|–vk2D.com/id446425943La inar Flow Past a Cylinder

24.4.4.1. Boundary Condition Sensitivity

1.Open the Adjoint Reporting dialog box (Figure 24.12: Adjoint Reporting Dialog Box (p. 806)).

Design → Adjoint-Based → Reporting...

Figure 24.12: Adjoint Reporting Dialog Box

2.Select inlet under Boundary choice and click the Report button to display a report in the console of the available scalar sensitivity data on the inlet:

Updating shape sensitivity data.

Done.

Boundary condition sensitivity report: inlet

Observable: force-drag

Velocity Magnitude (m/s): 40 Sensitivity ((n)/(m/s)): 54.556259

Decrease Velocity Magnitude to decrease force-drag

3. Close the Adjoint Reporting dialog box.

24.4.4.2. Momentum Source Sensitivity

1.Open the Contours dialog box.

Results → Graphics → Contours → Edit...

2.Select Sensitivities... and Sensitivity to Body Force X-Component (Cell Values) from the Contours of drop-down lists.

Figure 24.13: Contours Dialog Box When Plotting Adjoint Fields

3.Enter 25 for Levels.

4.Click Compute and then Display to view the contours (Figure 24.14: Adjoint Sensitivity to Body Force X- Component Contours (p. 808)) and then Close the Contours dialog box.

vk.com/club152685050Using the Adjoint Solver|–vk2D.com/id446425943La inar Flow Past a Cylinder

Figure 24.14: Adjoint Sensitivity to Body Force X-Component Contours

Figure 24.14: Adjoint Sensitivity to Body Force X-Component Contours (p. 808) shows how sensitive the drag on the cylinder is to the application of a body force in the -direction in the flow. If a body force is applied directly upstream of the cylinder, for example, the disturbed flow is incident on the cylinder and modifies the force that it experiences.

24.4.4.3. Shape Sensitivity

1.Open the Vectors dialog box (Figure 24.15: Vectors Dialog Box (p. 809))

Results → Graphics → Vectors → Edit...

Figure 24.15: Vectors Dialog Box

2.Select Sensitivity to Shape from the Vectors of drop-down list.

3.Select Sensitivities... and Sensitivity to Mass Sources (Cell Values) from the Color by drop-down lists.

4.Select wall from the Surfaces selection list.

5.Enter 1e-8 for Scale.

6.Click the Display button to view the vectors (Figure 24.16: Shape Sensitivity Colored by Sensitivity to Mass Sources (Cell Values) (p. 810)) and then Close the Vectors dialog box.