Journal 11

Entry date: 18.11.22

Chapter 2: Wind Tunnel

It takes more than wind to wind test a car. To be exact, it takes a three-ton fan, a steel tunnel measuring 11 metres in diameter and 163 metres in length, a heat exchanger the size of a wall, 24 hours of computer simulations, innumerable six-hour shifts, and as much steam and liquid nitrogen smoke as needed to wind test a car.

These wind tests are done to see how the car performs according to different criteria: contamination, aerodynamics, thermodynamics, climate comfort, energy efficiency, and internal environment. These criteria measure everything to do with wind, whether it’s the potential emissions caused by the material used to make the car’s interior, to the combination of rolling and air resistance which the car must overcome to move forward. The Polestar 1 has to undergo these tests, just like any other car.

Wind Tunnel

There are numerous design touches that influence the aerodynamics of the Polestar 1, the most distinctive of which is the active rear spoiler. Deploying automatically once the car reaches 100 km/h, and retracting when the car goes below 70 km/h, the rear spoiler is an innovative design solution meant to optimise the Polestar 1’s performance by creating downforce on the rear axle, and is something that needs to be tested during these wind tunnel procedures. Another design feature that needs to be accounted for are the lower outer grilles. Placed in deep recesses in the lower front of the car, these grilles can be opened and closed in order to efficiently cool the batteries and other electrical components.

These design features are tested under the watchful eye of Senior Analysis Engineer and Aerodynamics Ph.D. Lennert Sterken, and a team of wind tunnel personnel. “Of course, from an aerodynamics standpoint, we like the combination of a low roofline with an active rear spoiler” says Sterken of the Polestar 1.

From there, the Polestar 1 will make its way to the baking deserts of Arizona for further testing, as the wind tunnel does not provide all the conditions required for wind testing. It takes more than wind to wind test a car, and the Polestar 1 wind tunnel test was completed successfully. Stay tuned for Chapter Three, in which we detail the process that goes into dampers testing.

Fast Facts

Total length (testing area): 74.55 m

Total width (testing area): 29.90 m

Air path centreline length: 165.30 m