The science behind car window buffeting

AccuWeather

Ever crack your car window and feel that painful thumping sound? Scientists call it "buffeting", and Meteorologist Tony Laubach explores the quirky physics behind the booming noise - with a little help from his own storm chase experience.

Transcript

00:00In the automotive industry, they call this phenomena buffeting or booming.

00:09It's the name for that booming pressure that hits your ears when you roll down a window,

00:14and it's not just wind noise. Buffeting was originally discovered when they were looking

00:17at the sunroofs. Also, this could happen when you cracked open a window, so side window buffeting

00:22you often hear in the literature, especially the rear side windows. What's really happening?

00:27You've built a rolling wind instrument. When air rushes past that open window,

00:31pressure pulses in and out like your car's playing its own drum solo.

00:37This causes what we call resonance, so it's the same sort of phenomena like when you play a violin

00:41or a guitar and the body helps amplify the noise. The faster those swirls of air zip by,

00:47the quicker that thumping beat. The phenomena depends a lot on the speed,

00:51because that is going to control how quickly those little turbulent eddies that form over

00:56the outside of the car. Pass from the front of your open window to the back of the open window.

01:01And when your ears can't take another note, there is an easy quick fix.

01:05Just to open another window somewhere in the car a little slip. Usually the problem goes away.

01:09Those little lips on sunroofs aren't just for looks, they break up turbulence,

01:13but sometimes the pressure can literally blow the roof off.

01:16That truck just took out our sunroof. On a storm chase in 2011, the rapid pressure change of a

01:24passing semi was enough to explode our sunroof. A little bit of a related phenomena just in the

01:29sense that your big semi truck has, you know, it's moving a lot of air around it. At the front,

01:34ahead of the truck, there'll be a high positive pressure, and that's going to quickly change as

01:37you get towards the rear of the truck to a high negative pressure. So the next time your window

01:41starts thumping like it's dropping the bass. Remember, it's not your playlist,

01:47it's physics jamming along for the ride. For AccuWeather, I'm meteorologist Tony Lawback.

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