Aerodynamics News from Automotive Testing Technology Magazine

Why Renault is trusting the wind tunnel for Euro 7 prep

Michael Gabriel, senior aerodynamic engineer – utility vehicles, Renault — Wed, 19 Nov 2025 09:58:58 +0000

In preparation for Euro 7, Renault is scrutinizing the Master van in the wind tunnel. It will be some time before CFD fully aligns with wind tunnel results, but the new Renault Master serves as an exemplary aerodynamics success story. By Michael Gabriel, senior aerodynamic engineer, Renault utility vehicles department

Large utility vehicles significantly trail their passenger car counterparts when it comes to aerodynamic development. There are many reasons for this, including less stringent regulation, longer product cycles, poorly adapted resources and different customer priorities, but the winds of change have finally arrived.

Euro 6 regulations began pushing many larger vans into the category affected by the CAFE standards, and another significant step will be made with Euro 7 regulations set to take effect in 2027. Fierce competition is forcing OEMs to reduce their development cycles to stay competitive, while customers are being bombarded with information about the potential for operational cost reduction thanks to aerodynamically optimized vehicles.

Finally, with the December 2024 inauguration of the Automotive Test Section (ATS) at DNW’s Large Low-Speed Facility in the Netherlands, the large utility vehicle industry has a turnkey solution for precise aerodynamic measurement. In fact, the ATS is in complete accordance with the Worldwide Harmonized Light Commercial Vehicle Test Procedure requirements. This perfect storm of events will inevitably accelerate the shift toward more aerodynamically efficient utility vehicles.

When I was assigned as chief aerodynamic engineer on the new Renault Master project (XDD) in early 2018 – during the business strategy phase and just before the preconcept engineering kick-off – aerodynamic optimization for large vans was close to non-existent at the company. However, a competitor that had just won a coveted award was making a significant marketing effort to promote its world-class aerodynamic performance, which caught the attention of top management.

At the kick-off event a few weeks later, it was announced that the XDD Master would be the world’s most aerodynamic large van at launch. It was an incredible challenge. It took more than three years of focused teamwork to achieve the goal. Using a combination of competitor deep-dive analysis, hundreds of CFD calculations, around 200 hours of reduced-scale wind tunnel testing and regular intensive taskforce brainstorming, the general shape, engine cooling and exterior features were optimized. The achievement was confirmed during WLTP certification testing at DNW.

The result is a new Master large van family with 20% less drag and considerably reduced energy consumption. This means lower operating costs but also increased range and crosswind stability and, most importantly, without a negative impact on the vehicle’s utility, access, ergonomics or payload. The ‘advanced aerodynamics’ were specifically cited by the 25 international journalists that voted the new Renault Master IVOTY 2025.

While the XDD aero project can be considered a success at this point, the story continues with prep for Euro 7 certification. This month we will perform the first Master pre-Euro 7 certification testing using the wide-belt system for dual-wheeled utility vehicles. It’ll be a chance to test and perfect the Euro 7 aero package while also making our first use of the rolling resistance system in the ATS.

As I look back on my experience with this project, one subject particularly stands out: the issue of computer simulation versus physical testing. Clearly CFD will continue to gain importance and use as it is constantly improving. However, several large hurdles remain, which prevent an extremely accurate correlation with physical testing. The main limitation of CFD simulation is that it does not take into account model deformation.

At the 140km/h measurement speed of WLTP testing, things move a lot. Rubber air dams bend back, doors and hoods move outward, wheel arch liners and underbody panels vibrate, and the flexible air guides for engine cooling deform considerably. In addition, the tires and chassis change shape and position under the weight of the vehicle. None of this is taken into account by CFD, as the calculation burden would increase enormously.

In addition, utility vehicles have a huge wake compared with passenger vehicles, which accounts for a majority of the drag. A slight miscalculation in wake balance can have a large impact on the CdA result calculated by the software. Having compared a large number of wind tunnel tomography images and CFD wake calculations, I know that they are very similar but never identical. I believe a large part of the error in correlation I witnessed was caused by this discrepancy.

Therefore, I learned to use CFD for what it’s great at: visualizing the airflow. With CFD you can quickly detect early detachment at the rear, areas of localized turbulence and leaks in the air guides. There’s no better tool to explain to the architectural or design department why a change is needed. But when you need the precise drag value for a project milestone, or when it’s time to tweak the air dam or rear roof drop to balance the wake, you have to spend some time in the wind tunnel.

This thought leadership piece was published in the September edition of ATTI. Read the magazine online for free – it’s packed full of news, interviews and features, including how to maintain transparency in testing, the story behind the new Nissan Leaf, and the latest in battery testing and simulation

Automotive Testing Expo North America opens next week!

Rachel Evans — Wed, 15 Oct 2025 07:57:37 +0000

This year’s Automotive Testing Expo North America will take place on October 21-23 in Novi, Michigan. The free-to-attend exhibition offers an unmissable opportunity to gather insights for anyone involved in vehicle development, testing and engineering.

With more than 250 solution providers, The Future of Automotive Testing Conference and the Innovation Showcase, it’s the ideal place to discover new solutions, share ideas and build valuable connections.

There will truly be something for everyone, whether you’re an NVH specialist seeking new acoustics testing tools, an EV engineer in need of high-voltage test equipment, an ADAS expert looking for the latest lab systems, or a simulation specialist in need of a tool or a test driver searching for a new vehicle rental partner.

The Innovation Showcase will take place on day one and day three, enabling visitors to learn more about some of the latest technologies on display. Its interactive format is always a big hit. On day two, ATTI will host The Future of Automotive Testing Conference, beginning at 9:55am with an onstage interview featuring ATTI columnist Jon M Quigley, and with a program that features a wealth of influential industry figures.

Serving as the testing sector’s foremost communications platform, ATTI will also report live news throughout the show and gather intelligence for upcoming magazine issues. Don’t hesitate to share your ideas or news with ATTI.

For a comprehensive preview, see the September edition of Automotive Testing Technology International magazine.

Automotive Testing Expo North America will take place at the Suburban Collection Showplace in Novi, Michigan, on October 22-23. Visit the expo website to register for your free expo pass.

Automotive Testing Expo North America: Two weeks to go!

Rachel Evans — Wed, 08 Oct 2025 09:37:08 +0000

With two weeks to go until Automotive Testing Expo North America 2025 (October 21-23), here are ATTI’s top reasons to visit

The Future of Automotive Testing Conference

This day of high-level content will explore various topics and provide an engaging opportunity to learn from and connect with industry peers. Situated among the exhibits, it will have a relaxing atmosphere, and visitors will be able to dip in and out at their leisure. A highlight will be ATTI’s on-stage interview with Jon Quigley, who worked for Volvo for many years and now runs his own company, Value Transformation. With his broad experience and portfolio of contacts, he’s a very good person to know. He loves sharing his thoughts, too, hence his new gig as ATTI’s regular columnist.

Read Quigley’s latest column on p36 of the September issue.

Also during the conference, Venkat Adusumalli, software engineering manager at Stellantis, will reveal how Stellantis is using AI to accelerate E/E system testing and validation workflows. Click here for a pre-show interview with him.

Innovation Showcase

The free-to-attend Innovation Showcase also provides an interactive platform for learning about new technologies. Speakers will welcome questions and discussion after their presentations, making it a great way to explore ideas together. Like the conference, it will take place within the main hall, so it will be very easy to listen in while wandering through the exhibits, or to come and go throughout the day.

Technology debuts

The industry is moving quickly and it can be a challenge to keep up. Every year there is an abundance of new technologies on display. Some are incremental improvements to existing products, others are entirely new. It’s always surprising how companies find ways around bottlenecks. Often, these developments emerge from ongoing conversations between supplier and customer, ultimately benefiting multiple companies.

Read ATTI‘s comprehensive expo preview in the September issue.

Face-to-face discussions

It sounds obvious, but the most fruitful conversations are usually the ones that happen in person – it’s how journalists find the best stories. Year after year, exhibitors and visitors report having forged unexpected collaborations at the show, in the form of technology tie-ups or service partnerships.

Detroit’s revival

A lot of money has been plowed into Detroit in recent years, as evidenced by the stunning renovation of Michigan Central Station, which is well worth a visit. Much of the investment has been in the tech sector. Eleven years ago – when the station was still derelict – ATTI took a tour of some of the labs at GM and what was then the FCA headquarters (see The right wave length, November 2014, Seasonal highlights, September 2015, and Powerbase, March 2015). The facilities were impressive then and are even more so now, thanks to several years of investment in innovation leading to Detroit’s resurgence as an automotive powerhouse.

Visit the Automotive Testing Expo North America website to secure your FREE pass, which will give you access to the expo, the Future of Automotive Testing Conference and the Innovation Showcase

Father and son build Champ Car-inspired Hammerhead with Evolution Measurement aero support

Zahra Awan — Mon, 29 Sep 2025 14:56:33 +0000

Cavan Cameron, a student at Purdue University (Indiana), and his father, Russ Cameron, have developed a unique street/race hybrid, ‘Hammerhead’, for events such as Global Time Attack, building on components from 1994–2002 Reynard Champ Cars. The project marks the first use of such technology in a grassroots time attack competition. Supporting the car’s advanced aerodynamic development, Evolution Measurement is supplying EvoScann P8-A miniature pressure scanners, enabling real-time, high-fidelity aerodynamic data acquisition on track.

“This isn’t just a car, it’s an engineering thesis on wheels,” said Cavan Cameron. “Working with Evolution Measurement and their EvoScann technology gives us the precision data we need to validate our aero package under real racing conditions. It’s a game-changer for a grassroots team pushing the boundaries of what’s possible.”

Race car specialist Brendon Cleave, responsible for aerodynamic development and integration of EvoScann P8 units on the project, said, “Having access to EvoScann miniature pressure scanners allows us to map surface pressures and fine-tune wing angles, diffuser performance and underbody flow, all critical in time attack. We’re not guessing. We’re measuring, learning and evolving.”

The project began as Cavan’s senior internship and grew into a full-scale engineering endeavor, fuelled by his father’s lifelong love of second-generation Firebird Trans Ams and the pair’s mutual obsession with race-bred innovation.

EvoScann P8

The EvoScann P8-A miniature pressure scanner is a compact, rugged and ultra-precise data acquisition system designed for motorsport, aerospace and wind tunnel applications. Capable of capturing up to eight channels of dynamic pressure data at high sample rates, it is designed for mapping airflow over wings, splitters, diffusers and bodywork.

After competing at World Time Attack Challenge Sydney, Cameron plans to continue developing and testing the car at other US events, including Gridlife, Global Time Attack and Super Lap Battle. Each outing will serve as a rolling laboratory, with performance guided by EvoScann data.

Innovation and engineering at Alpine

Zahra Awan — Tue, 27 May 2025 15:57:21 +0000

Following on the heels of two episodes dedicated to history and design, the latest episode of the ‘Alpine 70 Years’ series focuses on the theme of innovation and engineering.

Through the testimonies of four experts, this third instalment takes viewers behind the scenes at the brand’s various engineering sites.

Robert Bonetto, VP, Alpine engineering projects; Sovany Ang, VP, product performance, Alpine; François Champod, vehicles director, Alpine Racing; and Olivier Guintrand, VP engineering, Alpine Cars, each shed light on the cult of innovation that has always guided the brand, from Jean Rédélé to the present day. This approach is particularly relevant at a time when Alpine is rising to the challenge of reconciling electrification and driving pleasure.

“The role of the Alpine Cars engineering team is to develop Alpine’s road cars and the innovative technologies that will guarantee their performance,” commented Robert Bonetto.

“At Alpine, we support our engineering and design teams in this relationship with customer expectations. The world is changing, customers are evolving, and new expectations are emerging,” said Sovany Ang.

The experts provide insights into the synergy that exists between Alpine motorsport and road cars. This symbiosis is now taking on a new dimension with the development of the Alpine Hypertech entity, which puts racing know-how directly at the service of innovation within Renault Group.

“With Alpine Racing Hypertech, we’re creating a high-tech structure, a real showcase for Renault Group and Alpine engineering,” added François Champod.

In related news, Alpine’s engineering teams continue to test the A390, the company’s first sport fastback, finalizing development on a wet track at Michelin’s Ladoux complex. The tests have demonstrated the A390’s chassis balance on slippery roads using Alpine Active Torque Vectoring. Click here to read the full story.

Ansys, Volvo and Nvidia slash aero simulation time

Rachel Evans — Wed, 26 Mar 2025 09:44:57 +0000

Following Volvo’s recent announcement that it is using AI-driven simulation in its safety development, Ansys has revealed a breakthrough in aerodynamics simulation through its collaboration with Volvo Cars and Nvidia.

Using the combination of eight Nvidia Blackwell GPUs for the solver and CPU cores for meshing, the companies state that they have reduced total simulation run time from 24 hours to 6.5 – enabling multiple design iterations per day, facilitating more optimization studies for electric vehicles and expediting time-to-market.

To enhance the energy efficiency and driving range of the fully electric EX90, Volvo Cars and Ansys scaled Fluent to eight Nvidia Blackwell GPUs, creating an optimized end-to-end workflow where meshing took just one hour and the solver 5.5 hours. This represents a 2.5x speed increase in solve time compared to running the same simulation on cost-equivalent hardware with 2,016 CPU cores. This technology combination enables Volvo Cars to conduct multiple CFD simulations per day, enabling rapid evaluation of design variants and accelerating design optimization.

“Using Ansys simulation has the potential to help our teams obtain favorable designs and carry out virtual testing in much less time than traditional approaches allow,” said Torbjörn Virdung, technical leader CFD, Volvo Cars.

“To make our products more efficient, we must first take stock of the tools and solutions we’re using to get there. In this case, the capability of Ansys Fluent can allow us not only to perform extremely high-fidelity analyses, but the added Nvidia infrastructure supercharges the computation, so we can consider a greater number of design possibilities and reach an optimal car design faster.”

According to Ansys, this accelerated process could help Volvo Cars meet emissions, range and efficiency standards, such as Worldwide Harmonised Light Vehicle Test Procedure (WLTP) requirements.

Shane Emswiler, senior vice president of products at Ansys, said, “This breakthrough underscores how GPU-accelerated simulation can drive innovation and get products to market faster. The combination of high-fidelity modeling and extreme solver speed empowers customers to run more simulations and maximize the results to develop more performant products.”

“The efforts of Ansys and Volvo Cars showcase the exceptional performance and scalability of our latest Blackwell infrastructure offerings and its applicability to engineering simulation,” said Tim Costa, senior director of CAE, EDA and quantum at Nvidia.

“Together with software partners like Ansys, we are paving the way for the future of computer-aided engineering and scaling to unprecedented heights, empowering our customers to solve their most complex challenges.”

Bugatti advances aerodynamics with Tourbillon development

Rachel Evans — Mon, 10 Mar 2025 13:04:00 +0000

In the latest episode of Bugatti’s New Era video series, the company discusses how it is pushing aerodynamic performance further with the Tourbillon, which was first revealed to the public in June 2024 and refines the low-drag foundation of its predecessor, the Chiron. “The Tourbillon’s predecessor, the Chiron, was already a low-drag car, but with the Tourbillon, we need to do better than that,” said Paul Burnham, Bugatti’s chief vehicle engineer.

Development began with CFD simulations to explore performance potential. Fifteen months before its unveiling in June last year, Bugatti’s engineering team tested a half-scale model in a wind tunnel in Italy.

“This test represents the first validation of the scale-model. This is the first test in which we assessed different design volumes, and different changes to the car,” explained David Šoštarić, head of aerodynamics and thermal management at Bugatti Rimac.

It was used to fine-tune high-speed performance before shifting focus to handling and dynamic efficiency.

The test model was built from 250 3D-printed components and fitted with over 100 pressure taps across its body panels. By measuring mass flow, static pressure, and air velocity at every key point, engineers validated their expected performance profile – crafted using advanced simulation tools.

Bugatti’s engineers used data-driven insights to refine the Tourbillon’s aero package. They reduced the car’s frontal area, incorporated an advanced rear diffuser and streamlined the cockpit’s exterior profile – all key improvements that build on the Chiron’s design.

The goal throughout the Tourbillon’s development was clear: optimize drag coefficient and airflow across the entire car. Months of work led to a new benchmark in performance. As a result, the Tourbillon can reach its top speed without deploying its rear wing while maintaining exceptional stability.

As engineers refined simulation models with real test results, the Tourbillon progressed from a scale model to a full-size prototype over the next year, requiring increasingly larger wind tunnel facilities.

Tourbillon is designed for maximum speed and stability

“We’ve moved on from a scale-model wind tunnel to a full-sized facility, continuing our program of validating the Tourbillon’s aerodynamic performance. Only now, we are using a full-scale prototype, which represents a natural step in enhancing calibration of our simulation tools, getting that next degree of accuracy in results,” said Burnham.

After years of dedicated work, the first experimental prototype validated the aero team’s simulations, paving the way for more advanced prototypes.

“The Tourbillon is a completely new program; we started from scratch. We are merging over a century of expertise in combustion-engine power with state-of-the-art electric performance. The new hybrid system is a significant change from Bugatti models of the past and makes the cooling system much more complex. But that’s why we have taken the detail to the next level; looking intensively at the airflows through the radiator channels at the front, through to the intakes behind the door within the iconic Bugatti C-line, to ensure that our digital simulations align with the physical model and deliver enough cooling to manage the car’s performance.

“The Tourbillon has been created by teams dedicated to the pursuit of perfection. Everyone has been fully committed to making the Tourbillon a new benchmark for the automotive industry, and it is a true testament to the skill and passion that has fueled its development,” said Burnham.

Pressure taps were used to capture data across the car’s exterior

Aptera takes solar EV to the Mojave Desert to validate efficiency

Rachel Evans — Thu, 06 Mar 2025 17:26:16 +0000

The first production-intent validation vehicle in Aptera’s solar car development program has been put through its paces at a proving ground in the Mojave Desert to verify its core efficiency.

This included coastdown testing to measure aerodynamic, rolling and powertrain losses. According to the company, the solar EV took over three minutes to decelerate from 60mph to a complete stop, even while traveling uphill. Based on Aptera’s calculations, this coastdown distance is significantly more than any other vehicle on the road today, gas or electric.

Aptera also conducted aerodynamic tuft testing, applying tufts to critical areas such as the wheel fairings and vehicle gaps. This test helped to confirm that real-world airflow matched Aptera’s computer simulations, enabling engineers to fine-tune fit and finish for maximum efficiency gains.

An extended highway drive cycle test was also performed covering hundreds of miles while monitoring the solar EV’s energy consumption. Aptera says that the data showed that its mathematical simulation model predicts real-world efficiency within just a few percent – a major validation of the vehicle’s aerodynamics, drivetrain and overall design.

“Our validation testing confirms that we’re on track to achieve our target energy consumption of roughly 100Wh/mile – unlocking a level of efficiency that makes solar mobility possible in a way never seen before. What started as Matlab calculations is now coming to life on the road. This is the future of transportation,” said Steve Fambro, co-founder and co-CEO of Aptera.

Aptera is already developing its next validation vehicle, focusing on improvements like tighter panel gaps and a design-intent weight profile with optimized parts. Once completed, the team will take it back to the track for another round of rigorous testing. This will include a range test, running the vehicle from a fully charged battery to 0%. Engineers will also assess its real-world solar charging performance to confirm daily solar range estimates.

More on the analysis program behind Aptera’s solar EV in the September 2023 issue of ATTI.

Stellantis invests in wind tunnel technology for EVs

Adithya Gopal — Fri, 25 Oct 2024 11:25:10 +0000

To augment its aerodynamics development for electric vehicles, Stellantis has invested US$29.5m in Moving Ground Plane (MGP) wind tunnel technology at its research and technical center in Auburn Hills, Michigan, USA.

The upgraded wind tunnel can measure and reduce airflow resistance from wheels and tires, which accounts for up to 10% of total real-world aerodynamic drag. The wind tunnel simulates real-world travel while enabling test vehicles to remain static. Belts suspended by cushions of air enable wheel movement at all four corners, while a fifth belt runs longitudinally beneath the vehicle, mimicking on-road travel conditions. This realistic simulation enables more precise testing and aerodynamic improvements.

Optimizing aerodynamic efficiency is vital to increase driving range in EVs. This contributes to improved efficiency, benefiting customers with longer EV ranges. This could also reduce battery sizes, which in turn could lead to cost and weight reductions.

Mark Champine, senior vice president and head of North America engineering technical centers, said, “That’s what makes this investment so critical. By reducing drag, we improve electric-vehicle range and, ultimately, the overall customer driving experience.”

The investment in MGP technology will benefit multiple Stellantis brands that will be able to optimize aerodynamics. The upgraded wind tunnel also provides a valuable complement to virtual development tools.

The new facility also debuts vital automation capability. Changes to wheelbase and track testing, which can take as much as two hours in conventional wind tunnels, can now be done in minutes, with the according real-time data collection and increased automation reducing development time.

While Stellantis already implements MGP technology at other facilities, those sites are focused on smaller vehicle platforms. The upgraded Auburn Hills facility will be capable of accommodating larger vehicles, particularly the STLA Large and STLA Frame platforms.

The measuring platform and and turntable that comprise the heart of the MGP equipment weigh 137 tons, rest on a concrete foundation and are supported by a specially designed steel frame. The tunnel, capable of generating wind speeds of more than 160mph, has been in continuous operation since 2002.