What’s that throbbing noise? How to prevent wind buffeting while driving
The strange rippling noise you hear when you have the windows down in your car is often caused by a phenomenon known as "wind buffeting." Below we dive deep into why it occurs and what you can do to prevent it the next time you're out on a drive.
It's a warm day, the sun’s out, and you’re out for a drive. Time to roll down those windows and sing at the top of your lungs!
Nothing increases endorphins quite as fast, but if you have a newer car at a certain speed, the helicopter sound vibrating from the windows can quickly become unbearable. Those windows go right back up… and the fun in the sun is over.
That rippling noise you hear is called the buffeting effect—or wind buffeting—and according to Professor Paul Walsh, of the Dept. of Aerospace Engineering at Toronto Metropolitan University, it’s due to aerodynamics.
“You have basically air that's flowing over the car as you're driving along, and that air tends to be turbulent, and buried within that turbulence are small, little fluctuations in pressure and velocity,” he explains. “So as the air passes over the car, it will cause oscillations at the resonant frequency inside the car, and that's what you hear.”
Wind buffeting occurs when air flows over the car and interacts with the open windows, creating turbulence and pressure changes inside the vehicle. (File image)
LEARN MORE: What is turbulence and how predictable is it?
Walsh adds that the thumping sound is the tradeoff for fuel efficiency and driving stability.
"With more aerodynamic cars, the air flows closer to the surface of the car—as if you were holding, let's say, a bottle or something—you're just blowing over the top of it," says Walsh. "With modern cars, you have the air passing over that little gap in the window, and it's just enough to set off that resonant frequency inside the car.”
For those who love jamming out to their favourite song while driving, there are some things you can do to lessen the buffeting effect and still enjoy some wind in your hair.
“You can adjust the frequency of the sound body by changing how much the window is open, because one of the things that defines the frequency is basically how much of a gap you have,” suggests Walsh. “You could open the window considerably larger, and you get so much air passing through it; the lack of smoothness of the interior of the car tends to break up that resonant frequency a fair bit, but you can't quite get rid of it completely.”
Combine the science with singing a little louder, and I think we might’ve just found a solution!