Nissan's engineering and design teams maximize efficiency with a decade of aerodynamic know-how
To the frustration of meteorologists around the world, the weather will never be truly predictable. But at an advanced wind tunnel research facility near Paris, a team of Nissan technicians has a special power at their fingertips. With the flick of a switch, they're able to precisely control the forces of nature – everything from a miniscule breeze right up to the winds in the most powerful tropical storms.
Their goal: perfect the art of automotive aerodynamics.
"The objective is to reduce the aerodynamic drag of the vehicle, which basically means making it easier for the car to cut through the air," said Sarwar Ahmed, aerodynamics engineer at Nissan Europe.
Air can create a huge amount of resistance. Aero forces increase with speed, meaning the car has to work exponentially harder to maintain forward motion against the oncoming air.
For electric vehicles, reducing drag is even more crucial. On long-distance, high-speed driving without an efficient aerodynamic design, "the vast majority of your battery energy would be used simply to push through the air," said Sarwar.
Sculpting a shape
As a result, every millimeter of a car's design needs to be meticulously evaluated to ensure its shape is as streamlined as possible. The best place to test this is in a giant wind tunnel.
"During the early stages of vehicle development, Nissan will have more than one styling concept," said Sarwar. "We use the wind tunnel to provide feedback on what initial features or concepts work better or worse for aerodynamics. This begins by defining the proportions or the general shape of the vehicle, a stage where there can be quite significant changes."
It's not just the shape that impacts a vehicle's aerodynamic performance. Sometimes, refining just one feature can lead to major improvements.
"The wheels and tires contribute around a third of the vehicle drag," said Sarwar. "A relatively small part like wheel deflectors can guide the flow of air around the tires. Similarly, the grille shutters that close off air going into the motor bay make a massive improvement to the drag."
Sarwar Ahmed, aerodynamics engineer at Nissan Europe
One feature that is often adapted from wind tunnel testing is the position of the exterior side mirrors. Through computer analysis of airflow over the test model, the team can identify where vortex shedding (areas of low pressure) around the mirrors is strongest, which can have the effect of pulling the car back. To mitigate this on the all-new electric Nissan Ariya, for example, this means "the mirror location has been flag mounted, instead of sail mounted," observes Sarwar. "This is better for aero acoustics too."
Finely Tuned, Ferocious Power
To capture its sensitive scientific data, the wind tunnel is purposely built for its field of physics. A moving ground lets the vehicle's wheels rotate to simulate driving on a road. The floor also sucks air in front of the car, increasing the accuracy of measurements.
"The entire thing sits above a giant balance below ground that can detect the smallest of forces and torque measuring in six degrees," said Sarwar.
Despite these delicate features, the wind tunnel boasts serious power. At full throttle, the turbine's huge blades can generate a sustained windspeed of up to 240km/h – equivalent to a powerful Category 4 hurricane* – all contained within four walls. Although, as Sarwar admits, "that is a bit excessive for us. We tend to only need to test at 140kph."
While testing at such speeds can be a lot of fun, it all comes back to a serious purpose: saving energy output from the vehicle, thereby cutting emissions in cars with combustion engines or helping EVs go farther. As the world switches to electric, Sarwar points out that aerodynamic development and testing will only have to increase.
The new Nissan Ariya puts this ethos at the heart of its design. Following wind-tunnel testing, its sculpted shape means it is expected to be the most aerodynamically efficient model in all of Nissan's crossover lineup.
"The Nissan Ariya is the result of a truly global effort," said Helen Perry, head of Electric Passenger Cars & Infrastructure for Nissan in Europe. "Together, we worked to bring new creative aerodynamic features to Ariya which – combined with its powerful performance, connected technologies and revolutionary new EV design – will with no doubt meet our customers' expectations."
In the race towards greener personal mobility, you can be sure that more Nissan models will be tested against the storm-force power of the wind tunnel.
Helen Perry, head of Electric Passenger Cars & Infrastructure for Nissan in Europe
* Measured on the Saffir Simpson scale