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Top 10 sleek car aerodynamics CFD studies

By Simon Fischer

Without doubt, car aerodynamics is one of the most commonly known Computational Fluid Dynamics (CFD) disciplines. And for sure Formula1 has had a huge impact on the democratization of car aerodynamics CFD. And while the mainstream learned about vehicle aerodynamics watching the Schumachers, Hamilton and Vettel, I got tied into car aerodynamics simulations by fighting a nonsense fight with one of my colleagues. The matter of dispute:

Which is the king discipline of all CFD?

My colleague had a very clear opinion: The one-and-only, the ultimate, most exciting and prestigious discipline of CFD – is… well he was a technical specialist for car aerodynamics CFD at the time – so… obviously biased; I was an internal combustion engine CFD engineer back in the days, which – obviously and way more objectively- was the most prestigious discipline back then 😉

But all jokes aside, you can’t deny that car aerodynamics CFD has a lot of appeal and is clearly an all time favorite of the masses, the petrol/Lithium heads and the CFD geeks alike.

Triggered by that flow, and given that I have seen a dozen of cars go through the virtual Simcenter wind tunnel over the years I thought it was about time to line up some of my favorites in the first of its kind car aerodynamics CFD show. That being said, enjoy…

My 10 favorite car aerodynamics CFD studies and visualizations

10. Le Mans – an all time classic in our validation suite

The LeMans car has been among the Simcenter STAR-CCM+ demonstrator cases since I joined the company. It has been featured in hundreds of demonstrations, and become an intrinsic part of our performance benchmark suite. As such, over the years it probably has seen all huge cloud vendor HPC clusters and almost any new compute hardware, from GPU through GPU and even ARM, that made it into public. Along with this history comes a line-up of visuals. My favorite is this one:

9. Pandora – In DesA’s technology demonstrator

InDesA is a German engineering consultancy company for Automotive OEMs and suppliers with experience of over 20 years in simulation and design analysis of complex fluid flow, heat transfer and acoustic systems. They designed a 100% virtual demonstrator vehicle to easily showcase their simulation capabilities to a wide audience while ensuring a realistic level of geometric fidelity. As such -even though you will never be able to find it on the streets – its fidelity and appeal matches that of a real car: The Pandora.

Numerous times did we have the pleasure to witness the Pandora in virtual action at Simcenter conferences over the last years. The animation below is not just a pure car aerodynamics CFD. It is a transient vehicle thermal management simulation to understand the thermal soak during a stop and go drive cycle scenario.

8. CURE Mannheim Formula Student race car

There are many awesome Formula student teams out there in the world. With an equally big number of great race cars and respective car aerodynamics CFD simulations. Representative for all of those I have picked one that has been displayed with one of the most impressive FS vehicle animations. This is race car by the CURE Mannheim team:

7. Maserati Ghibli – The Simcenter demonstration machine

Thanks to an agreement with Maserati , Siemens is allowed to leverage the Ghibli’s full vehicle assembly to showcase CAD and CAE capabilities. Needless to say that a vehicle that exists in reality is the perfect candidate to demonstrate how to model the complexity of real products. And so the Maserati has been used to both verify simulation workflows and demonstrate our simulation strength at many occasions. Our Engineering Services team for example undertook a complete vehicle thermal management simulation (VTM) including a complex stop-and-go drive cycle to asses thermal soak scenarios. This goes beyond classical car aerodynamics CFD, but is equally beautiful to look at.

6. AeroSUV – The FKFS Stuttgart benchmark car

Like the DriveAr (see#2) by TU Munich the AeroSUV by FKFS Stuttgart is an open access generic car geometry. To reflect the market trend of an increasing number of SUVs on the streets, the structure of the AeroSUV is similar to the one of the DrivAer, but representing a typical mid class SUV. Both geometries are accessible through ECARA website together with accurate test data. These factspotentially made the AeroSUV – together with DriveAR – one of the most CFD-studied vehicles on this planet. The animation below shows Simcenter STAR-CCM+ DES on the Aero SUV and a subsequent side-mirror aeroacoustics study.

5. SimRod – Simcenter’s ultimate technology carrier

In the first place the SimRod is not just a digital twin. It’s our Simcenter lab-on- wheels or in engineering speak: a (physical) demonstrator. Demonstrators are important because we can investigate those tricky engineering enigmas, but more importantly for the Simcenter story, we can check out the accuracy of the performance predictions created by our Simcenter and NX digital twins. This ability to double check the digitalized world in reality is a key success factor to creating a more truthful digital twin – rather than a less accurate, incomplete or “dirty digital twin”.

And so over the years the SimRod has been undergoing a vast amount of CAE studies, structural, system, and of course CFD studies have been carried out leveraging our ultimte work horse -or a bit more formally technology carrier. Among the many CFD studies, obviuosly car aero CFD may not miss. And for Hannover Messe 2022 the SimRod aerodynamics CFD simualtion even became a center showcase piece, enabling visitors to dive into the virtual windtunnel using Simcenter STAR-CCM+’s Virtual Reality.

4. Pandora 2 – InDesA’s electrified technology demonstrator

The times they are changing. And it is no secret that the automotive industry is undergoing a massive disruption with the rise of e-powertrains. As such it is no surprise that InDesA (see #9) has created a successor of the Pandora, the Pandora2: An electric, battery powered SUV that by no means lacks behind itS’ predecessor when it comes to care for detail, geometric fidelity and the desire to create a meaningful digital twin of a modern vehicle. Like the Pandora, Pandora 2 has produced amazing results since it’s rollout in 2022. Here are some of my favorites so far.

3. Corvette ZR1 – The CFD powerhouse

In the shear number of CFD studies using Simcenter STAR-CCM+, she potentially leaves them all behind: The Corvette ZR1. Like the Maserati (#7) Chevrolet’s sports car is luckily a part of the Siemens CAD geometry database as a full vehicle assembly since quite some time. As such, the Corvette ZR1 has undergone hundreds if not thousands of CFD simulations over the last years: Anything from external car aerodynamics, demonstrating the automatic handling of a realistic complex vehicle assembly, through brake cooling duct topology optimization, to fluid-structure interaction and design exploration of a rear-wing and so many more. The ZR1 has seen them all. Here is just a small excerpt of my favorite animations showcasing some of the aerodynamics studies:

2. DriveAr – TU Munich’s white mouse

The DrivAer model by TU Munich has become one of the powerhouse use cases to drive car aerodynamic research and CAE method developmen all over this globe. Due to the high fidelity, a comprehensive validation data set and the open access of the model, it has been adopted by academia and several automotive OEMs and CAE software developers, including Siemens. Here is my personal favorite car aero CFD visualization showing the DriveAr in Simcenter’s virtual windtunnel. Full blown transient LES, run on GPUs…overnight, and beautifully rendered:

1. The DeLorean DMC12

There is no other way: Despite all the amazing projects and outstanding car aerodyanmics CFD simualtion lined up before: It’s been out a while but the DeLorean aero CFD remains my personal number one. Why? Well because without it the world would still wonder whether or not the DeLorean could really fly…

Car aerodynamics CFD in Simcenter STAR-CCM+

I hope you enjoyed this first of its kind line up of outstanding car aerodynamics CFD simulations. If you want to learn more about the technical details of such simulations in Simcenter STAR-CCM+, check-out our solution spotlight on the topic:

This article first appeared on the Siemens Digital Industries Software blog at https://blogs.sw.siemens.com/simcenter/car-aerodynamics-cfd/