Compare a design change¶

In this tutorial you'll make a design change to the front wing from the first simulation tutorial: pitching it 2° about its leading edge. Then you'll simulate it against your first Run as a baseline and see what changed. On the way, you'll use Bramble's tools for generating new geometry, copying Assemblies, baselines and deltas.

Before you start¶

• Complete the first simulation tutorial. You need its DEMO Programme and DEMO01 Project, the front-wing Part, the Front wing Assembly, Map and Kinematic Setup, and the First front wing run with results.
• Select DEMO and DEMO01 in the header.

The set-up takes about 15 minutes, plus the time for the solve.

1. Make the new wing¶

Rather than exporting new CAD, you'll rotate a copy of the existing Part.

1. In the sidebar, under Setup & CAD, click Parts, and expand the Tutorial library.
2. In the front-wing row, click the icon in the Transform column.
3. In Transform Part: front-wing, enter:
   • New Name: front-wing-pitch2
   • Transformation Type: Whole Part
   • Transformation: Rotation
   • Rotation Origin* (mm): -1188 0 175. This is a point on the wing's leading edge. Geometry is in millimetres.
   • Rotation Axis*: 0 1 0, the spanwise (y) axis, so the wing pitches.
   • Rotation Angle: 2
4. Click Transform Part. When "Part Transformation Complete, new part successfully created" appears, the new Part is in the Tutorial library.

The new Part keeps the zone name fw. That means the same Template Case applies to it in exactly the same way, which is what makes the comparison fair.

2. Make a variant Assembly¶

Copy the Assembly and swap in the new wing.

1. Click Assemblies and expand the Tutorial library.
2. In the Front wing row, click the copy icon (Create Copy).
3. Change the Description to Front wing pitch 2, and click Save.
4. Open Front wing pitch 2. Remove front-wing with its remove icon, then click Add Parts and add front-wing-pitch2.

3. Create a Run with a baseline¶

1. Click Runs, then New Run.
2. In Create Run, enter:
   • Title: Front wing pitch +2
   • Baseline Run: click Select Baseline and choose First front wing run
   • Kinematic Setup: Front wing
   • Map: Front wing 50 m/s, the same Map as the baseline, so the Attitudes match by name (v50)
3. Click Pick Assemblies, select Front wing pitch 2, then click Create Run.
4. Open the Run and look at the CFD Setup tab. The v50 Attitude's setup has been copied from its baseline Attitude, and nothing is flagged in red. The methodology, workflow and Template Case all match the baseline.

4. Choose the checks for a modification¶

1. Open the Run Checks tab.
2. In the Checks Template row, click the pencil icon, choose Modification Checks, and click Save.

Modification Checks compares the mesh recipe with the baseline's. It also adds delta-geometry plots, which show where the geometry changed. See configure pre-checks.

5. Launch and solve¶

1. On the Summary tab, under Group Transitions, click Launch, tick v50, and click Trigger launch.
2. When Pre-Checks has completed, open Run Checks and look at the Delta Geometry plot in Select Pre-check Plots. It should show the wing's trailing edge moved and nothing else.
3. Click Mesh & Solve for v50 and confirm.

After the solve, the lifecycle runs Create Delta PostPro as well as the usual post-processing.

6. See what changed¶

1. Open Results. Both Runs are in the table. The new Run's row shows its delta values against the baseline.
2. Select both v50 Attitudes. Under Available Postpro → Plots, click Cp.
3. In the postpro viewer, turn on Switcher Mode and press - and = to flick between the two wings.
4. Optionally, click Generate Image Deltas, choose First front wing run's Attitude as the Delta Baseline, and submit. After a short while, the Image Deltas row shows exactly where the surface pressure changed. See generate image deltas.

Finally, sign off the new Attitude on the Run's Summary tab, as you did in the first tutorial.

Where next?¶

• Explore more changes at once. Build a sweep of Attitudes with generate a sweep.
• Deform rather than rotate. Bramble's morphing tools can bend, twist and scale geometry. See morphing and optimisation.
• Understand baselines. Read baselines and deltas.