Now that you have a mesh, you can set up and run a simulation on it. Do this step-by-step through the control panel, or, as shown below, by using a previously created and saved JSON file containing these settings.
Download the settings file to your computer by clicking the above link. If you started this tutorial by uploading a CAD model and generating a mesh, select the CAD option. If you started by uploading a mesh file, choose the Mesh option.
Click the three dot (...) menu at the top of the control panel.
Select Upload Settings.
Select the file you downloaded in step 1.
Once uploaded, you should see that there are no red dots alongside any sections in the control panel (all required settings have been assigned) and the Run Simulation button at the top is active. Before running the simulation, we'll need to create some outputs and set stopping conditions.
Create Outputs
For this simulation define outputs for the lift and the drag of the airplane at its current flight conditions.
To define lift and drag as output variables:
Click on + symbol next to the Outputs section in the control panel.
Select Surface.
Set Quantity to Lift (N).
Set Reference Frame to Body Frame.
Scroll to the bottom of the properties panel and click in the box to choose which surfaces to calculate lift over. Select the Airplane surface from the 3D Viewer or Geometry panel and then click outside the box to save.
Repeat steps 1-5, but select Drag (N) from the Quantity list.
Set Stopping Conditions
Stopping Conditions are used to determine when a simulation exits and saves results.
In the case of the Piper Cherokee, use stopping conditions based on the number of iterations, the residuals, and one of our custom output quantities:
Click on Stopping Conditions in the control panel.
Set Max Iterations to 2,000. This means that if the simulation hasn't met the other stopping conditions criteria by the time it has run 2,000 iterations, it will save and exit then.
Under Conditions, set Stop If to ALL Conditions are met. This means all the following stopping conditions must be met for the solution to save and exit early.
Click + Add Stopping Condition.
Set Output Name in the new stopping condition to be Lift.
Set the following:
Tolerance: 0.01%
Start at Iteration: 500
Averaging Iterations: 10
Iterations to Consider: 5.
This means that starting from the 500th iteration, the platform will calculate an average value of lift based on the last 10 iterations, inclusive. It will then compare the variation of this trailing average over the last five iterations, inclusive. If this varies by less that 0.01%, the stopping condition will have been met.
Run Simulation
If everything is set up correctly in the control panel, the Run Simulation button at the top will become active.
Clicking on this button will launch a new simulation and open a Simulation tab showing you the current status of the run. Once the simulation has finished, this new tab can also be used to analyze the results and create visualizations.
On the left of the 3D Viewer, you will see a collapsible Run Status summary. The Output monitors at the bottom will, once the simulation starts, show a graph of the residuals or other chosen output quantities. By watching these three components you can see the current status of the simulation and track its progress.
This sample project will run for 2,000 iterations. At this point it will stop, saving all of the data for the last iteration.
To run this simulation for additional iterations:
Click on Post-processing at the top of the control panel.
Select Setup Details.
Click the Copy to Setup icon at the top of the control panel. This will copy all the settings used in this simulation to the Setup tab, and set the initial conditions for a new run to be the values from the final iteration of the previous run.
Next Steps
Now that you've run a simulation, you can move on to:
Analyze the results
Visualize flow movement with Visualization Tools
Use the buttons below to choose.