Fast CFD Simulations - 3 Point Map in 3Hrs

bramble has been developed to allow engineers to run more simulations and do more analysis. To this end let us introduce our newest queuing option, ashdown.640. Enabling you to run fast cfd simulations, up to 4x faster. Below we will demonstrate how you can regularly run full-car simulations on a Three Point Map in just three hours.

Simulations have traditionally followed an ‘overnight’ turnaround philosophy in the automotive world, usually taking 8 to 16 hours to complete. This lets engineers submit jobs at the end of the day and receive results by morning. However, it doesn’t particularly matter for the engineer whether a simulation takes 8-hours or 16-hours as they still won’t be able to react to it until the next working day.

Many engineers view turning a simulation around in under 8 hours as the next milestone. This would allow engineers to submit jobs in the morning and review results before the end of the workday. Though in practice, even if submitted first thing, it probably won’t leave enough time to analyse the result and produce the next iteration.

However, things get really exciting when simulations take less than 4-hours (two simulations a day). Or better still, less than 3-hours (two simulations a day with time spare for analysis and design).

Ashdown – your new queuing option

In order to run fast cfd simulations and enable this 3-hour turnaround, we’re launching a new queuing option, ashdown.640. Ashdown leverages the latest Graviton instances on AWS, taking advantage of great scalability and deep pools to allow for high core-count simulations.

Moreover, simulations on ashdown.640 are charged at 9p/core-hour and have no queues (subject to capacity on AWS). And because it is bramble, we’ve handled all the integration – you simply need to select the workflow and queue in the CFD Setup tab.

Multi-attitude testing

At bramble, we firmly believe that testing over multiple flow conditions is the key to developing robust designs. To find out more on this, check out these articles on our kinematics models and running aero-maps.

Thanks to the power of bramble & AWS, running multiple attitudes is no more difficult than running a single one. So what better way of demonstrating the power of ashdown.640 than by submitting a Three Point Map on our F1 demonstrator model at the start of the day and getting all the result back by lunchtime.

launching our test for completing simulations in under 3 hours

To begin with bramble set the ride heights, configured the CFD model and performed its automated checking once the models were launched. The whole process took a couple of minutes to complete on this model. Once all checks passed, we submitted the attitudes to the ashdown.640 queue, which began running in parallel at 9:09 a.m.

In this case, these models are all full-car steady-state RANS with a mesh count of ~115-million cells. bramble uses auto-convergence checks to stop a simulation when forces have levelled to a desired tolerance.

Subsequently, this leads to a variance in run time, but the longest CFD simulation ran for 3,785 iterations, took 2-hours 21 minutes and cost £135.

Lastly, bramble received all models by 11:30 a.m. Processing forces and generating post-processing was completed in a further 20-minutes making the CFD simulations ready for analysis by 11:50am!