Methodology, workflow and Template Case¶
Every Attitude's CFD setup comes from three choices made together on the Run's CFD Setup tab. They answer different questions:
| Choice | Answers | Example |
|---|---|---|
| Methodology | Which CFD code, and which version? | v1806F (OpenFOAM v1806), a Star-CCM+ version, zCFD |
| Workflow | What kind of simulation? | TSFoam RANS 1806F, TSFoam DES 1806F, a MeanCalc, CHT or donor workflow |
| Template Case | What exactly to simulate: the recipe | Mesh recipe, boundary conditions, solution stages, forces, exports |
You supply the geometry and the conditions (the Map), and these three choices tell Bramble how to build and run the case.
Methodology¶
A methodology is a CFD solver at a particular version. It decides how Bramble writes the case files and reads the results. The version is part of the name, so moving to a new solver version means choosing a different methodology.
Methodologies belong to a Methodology Group, a family that shares the same Template Case settings:
- OpenFoam
- OpenFoam with CHT
- Star-CCM+
- Acoustic (zCFD)
Workflow¶
A workflow is a type of simulation for one methodology, such as steady RANS, DES, DES with MeanCalc, CHT, or an acoustic run. Behind the scenes it's an ordered set of steps that run on the HPC cluster: mesh, set up, solve, export, and so on.
Workflows are enabled per Account. You'll only see the workflows your Account can use, and a methodology only appears if at least one of its workflows is enabled. The list is shown on the Account Settings page. To add a workflow, such as DES, donor or MeanCalc workflows, contact support@bramblecfd.com.
The workflow runs inside the Mesh & Solve stage of the lifecycle. It doesn't add or remove lifecycle stages. Some workflows do change when Mesh & Solve starts, or what the CFD setup asks for:
| Kind of workflow | What changes |
|---|---|
| Donor workflows (donor mesh, donor solve, donor FRPM) | The Attitude is a recipient: it reuses another Attitude in the same Run, its donor. Its Mesh & Solve waits for the donor and starts automatically |
| Mapped inlet workflows | The CFD setup asks for a Mapped Inlet Source |
| AWS workflows | Must use an AWS queue |
| Workflows with Run-on or Extra Exports | Those buttons appear on the lifecycle table |
Template Case¶
A Template Case is the recipe: how to mesh the geometry, which boundary conditions apply to which zones, the solution stages, what to measure and what to export. It belongs to a Programme and one Methodology Group.
- The Methodology Group decides which settings the Template Case editor offers.
- The Template Case's workflows (optional) add workflow-specific settings, such as MeanCalc, and limit the solution stage to steady or transient.
- Settings can target workflows. For example, a Template Case can refine brake discs further only in thermal workflows, so one Template Case serves several workflows. See settings for specific workflows.
Making them match¶
Bramble doesn't stop you choosing a Template Case that doesn't suit the methodology or workflow. The CFD setup lists every Template Case in the Programme. It's up to you to choose a compatible combination. A mismatch usually shows up as a failed pre-check or a failed solve.
Good practice:
- Name Template Cases so their Methodology Group and intended workflows are obvious.
- Use Save to All to give every Attitude in a Run the same setup.
- If a Run has a baseline, the CFD Setup tab flags in red any Attitude whose methodology, workflow or Template Case differs from the baseline's. Differences make comparisons less like-for-like.
Related: CFD setup options · Simulation configuration · Create a Template Case