Mesh Cloning - Save Time & Money in your CFD Process

Testing geometries over multiple flow conditions is an effective method of producing more robust designs.

Where these flow conditions are changes in boundary conditions, such as velocity or yaw angle, there’s no need to regenerate the mesh for each test, this is where mesh cloning helps. By reusing the same mesh across tests, you can save both time and money. This not only reduces computational costs but also minimises the potential for inconsistencies between simulations, ensuring more reliable comparisons across different test conditions.

Introducing donor workflows

In bramble, we call the process of cloning a mesh from one simulation to another a ‘Donor Workflow.’ Using this workflow is straightforward—simply select it from a drop-down menu. bramble takes care of all the complexities involved in mesh cloning automatically. You can clone a mesh for RANS or DES simulations, or even clone a RANS simulation and use it for a DES solve. Let’s take a look at this, as an example, let’s walk through how to setup and run a mesh cloning example for a yaw sweep.

Step 1 – create a map

In bramble, you have the ability to define a Map, a set of test conditions over which a design is to be tested. To create a new map, go to the ‘Maps’ view and click ‘New Map,’ and then define the test conditions. For this example, we’ll test five different yaw angles.

Step 2 – create a run

If you already have a baseline case, click ‘Create Child’ on the baseline, then choose your new map. bramble will create a copy of the baseline, duplicating all the model build and CFD setup information.

The run will be populated with lifecycles for each of the test conditions, or attitudes, in the selected map.

Step 3 – update CFD workflows

In the CFD Setup tab, assign the right workflows. One attitude will be configured with a standard RANS workflow. This will be the attitude from which the mesh will be cloned. All the other attitudes will have a RANS Donor workflow selected.

Step 4 – launch simulations

After setting everything up, you can launch the simulations as you normally would. Once the Pre-Checks complete, and assuming no issues come up, you can submit the attitudes to the cluster. However, with the Donor Workflow, there’s an important difference: at this point, you can only submit the standard workflow attitude (this is the one providing the cloned mesh). The other attitudes will have their ‘Mesh & Solve’ buttons disabled since they can’t be launched until the first attitude finishes and the mesh is ready.

Once the first attitude completes and generates the mesh, bramble will automatically submit the remaining attitudes for solving. So you won’t need to handle their submission manually.

This streamlined process not only reduces manual workload but also decreases the risk of errors when testing multiple attitudes, ensuring consistent and repeatable results across all simulations.

This approach simplifies testing across multiple conditions, saving both time and computational resources.