Over the past few months, we’ve been significantly expanding Bramble’s CFD mesh morphing capabilities. The latest release introduces a major step forward: parameter-driven geometry morphing, allowing deformations to be controlled using geometric variables such as camber, angle of attack, and component positioning.
This update represents an important step forward for CFD software for aerodynamics, transforming mesh morphing from a manual geometry-editing tool into a scalable solution for aerodynamic optimisation and automated design exploration.
From Manual Geometry Editing to Parametric Optimisation in CFD
In the initial release of Bramble’s mesh morphing tool, geometry changes were applied by manually moving individual nodes of the deformation volume. Whilst this allowed the user to change a geometry’s shape, it was more suited to making a one-off modification. Mesh morphing really comes into its own when used for optimisation and for this we need to be able to define a set of geometric parameters that can be adjusted during the optimisation. For example, on an aerodynamic wing these could be chord length, angle of attack and camber.
This latest update enables exactly that.
If you haven’t already read our overview of how Bramble’s morphing technology works, we recommend starting with that article first.
Defining Geometric Parameters in bramble
What is a Parameter?
Bramble’s CFD mesh morphing tool works by creating a ‘net’ or ‘deformation volume’ around a piece of geometry. When the nodes of the volume are moved, the geometry contained within is deformed. In order to produce more complex or controlled deformations we need to get multiple nodes moving in unison in proscribed fashion.
For example, to control angle of attack, we will want all the nodes to rotate about to proscribed origin and axis. Simply put, a Parameter is a rule that controls the motion of a set of nodes.
Creating a Parameter
Once a deformation volume has been created in Bramble, parameters can be defined via the Morphing modal by selecting View Parameters. From here, users can create new parameters or edit existing ones.
The process consists of three main steps:
1 – Select Nodes
Nodes can be selected either from the menu or directly within the viewport.
2 – Define the Parameter
Each parameter is given a descriptive name (e.g. Camber, AoA) and then the type of motion being defined is set. There are three types:
Translation – where the nodes moving align a defined vector
Rotation – nodes rotate about a defined origin and axis
Scaling –where the position of the nodes is scaled towards and away from a defined origin.
3 – Assign Node Weightings
Weightings define how much each node moves in the x, y, and z directions when the parameter is adjusted.
Having selected the deformation type and set the origin (for rotations and scales) and axis (for rotations), we can then set x, y and z weights for each node. This is done to control how much each node moves in each axis when a deformation is applied.
For example, perhaps we are controlling lateral position of a device. To do this we would set all the x and z weights to be 0, leaving y as 1. Thus, when a deformation is applied, the nodes will move along the (0,1,0) axis.
Using Node Weighting for Smooth Aerodynamic Deformation
Node weighting plays a critical role in achieving smooth and controllable geometry changes during CFD mesh morphing. To control camber of the example diffuser strakes, we might set the nodes at the maximum camber point to move by (0, 1, 0), but the adjacent nodes to only move (0,0.5,0), i.e. half as much. This smooths the deformation along the strake.
Additionally, where a part contains geometry of both the left and right-hand sides of a model, we might need to set the y-weight to be negative on the left-hand side nodes to achieve a symmetrical motion.
Diffuser Strake Optimisation Study
To demonstrate Bramble’s parametric optimisation CFD capabilities, we performed a diffuser strake optimisation study on a car geometry developed to the F1 2026 technical regulations.
Optimised Geometric Parameters
Three geometric parameters were varied:
Lateral position – varied by 100mm inboard to 50mm outboard
Camber – adjusted by moving the strake slot gap laterally by +/-50mm
Leading edge position – varied by curving the leading edge laterally by +/-50mm
Results
Initial Design of Experiments
An initial Design of Experiments (DoE) consisting of 15 simulations was generated with varied geometric parameters and using the Optimised Latin Hypercube method. This ensured good coverage of the design space with a limited number of CFD runs.
All models were run using:
-
Steady-state RANS
-
A single vehicle attitude
The predected aerodynamic forces (downforce and drag) were fed into a Kriging analysis. This analysis was then used to identify two further designs, one that maximised downforce and one that maximised efficiency (the ratio of downforce-to-drag), although both designs were very similar.
Aerodynamic Optimised Performance
Ultimately, it was the maximum efficiency design that performed the best producing the highest downforce and overall efficiency.
The optimised design versus the baseline:
– Moved laterally 18mm outboard
– Increased camber by 18mm
– Moved the leading edge 43mm inboard
The changes created a more highly cambered strake set at a higher angle of attack to the incoming flow.
The image to the right is a Delta Cp plot showing the change in pressure between the baseline and optimised strakes. There is a large increase in suction (lower pressures) inboard of the strakes as a result of the increased camber and angle to the oncoming flow. These lower pressure produce the additional downforce.
Interestingly, lower pressures can also be seen across the surface of the underfloor, showing the impact of the strakes isn’t limited to their proximity, but can impact a large surface area of the car.
The gif above compares the flow field at a longitudinal position through the strakes coloured by contours of total pressure (energy in the flow). It shows that the optimised strakes are producing stronger vortices down their inboard sides.
The gif above shows a top-down view of the flow going past the strakes. The increased angle of attack onto the stakes can be seen as can the increased outwash immediately behind them. Increased outwash is desirable as it helps expand the flow exiting the diffuser, pulling more flow under the floor and ultimately increasing downforce.
Wrapping up
Parametric CFD Mesh Morphing for Aerodynamic Optimisation
This study demonstrates how CFD mesh morphing with parameter-based control enables efficient and robust aerodynamic optimisation of complex components such as F1 diffuser strakes.
By embedding geometric intelligence directly into the mesh morphing process, Bramble allows engineers to:
-
Perform parametric optimisation in CFD with minimal manual intervention
-
Rapidly explore aerodynamic design spaces
-
Integrate geometry morphing seamlessly into automated optimisation workflows
This capability represents a powerful advancement for CFD software for aerodynamics, particularly in motorsport and high-performance vehicle development.
Contact us
See how bramble CFD could work for you
Discover more!
Find out more about some of bramble’s key features or bramble’s tailor built hardware for CFD options.
Related articles
Rolling Reports – A Smarter Way to Log and Share Your CFD Results
Every CFD engineer knows that the real challenge begins after the simulation finishes - turning...
Exporting Volume Data
Sometimes you may want to view your CFD results in a desktop tool like ParaView for further...
From Wind Tunnel to Web Browser: How Cloud CFD is Changing Motorsport Aero Development
Accelerating Motorsport Aero DevelopmentIn motorsport, every millisecond on track counts, and so...