What Causes That Awful Buffeting Sound When You Open One Car Window?

There’s a scientific explanation for that irritating 'whomp, whomp, whomp' sound, and a reason why opening another window fixes the issue
What Causes That Awful Buffeting Sound When You Open One Car Window?

We’ve all been there. Driving along on a fine summer’s day, feeling the warmth of the sun on our skin, thinking about how wonderful life is. But then you get a bit too hot and you think “I know, I’ll open a window to let some cool, refreshing air in,” only to be greeted by the sound of eardrum-popping bass.

You curse compromise and either sit there sweating like a Honda at a muscle car meet or sacrifice the serenity of the drive for some sweet fresh air, glaring at smug-faced drivers next to you pumping their air con.

But why does this buffeting happen? Why does it seem to be worse in some cars than others? Why does its severity depend on which window you open? And why does opening another window help? So many questions, and fortunately science has the answer.

Image via Wikimedia Commons
Image via Wikimedia Commons

It’s called the Helmholtz Resonance, and it’s the same idea as when you blow across the top of an open bottle to make a tune. It was discovered by German physicist Herman von Helmholtz, who explained that as air passes over the leading edge of an opening, such as a car window, it creates small vortexes – i.e. mini tornadoes.

These vortexes then compress and decompress the air in the cabin, creating waves of pressure, which your ears interpret as sound. So, the repetitive ‘whomp, whomp, whomp’ sound is the air in the cabin getting its butt kicked by the air passing outside the window.

Helmholtz explained that the smaller the hole and container of air, the higher pitched the sound. That’s why bottles make a tuneful hum and car windows, which open to a large cabin, make a low thumping sound.

What Causes That Awful Buffeting Sound When You Open One Car Window?

There are a few factors that can affect how severe it is. The buffeting tends to be worse in modern cars because they are more aerodynamically efficient, meaning air passes closer to the side of the car. It’s the same reason it tends to be worse if you open a rear window, because the front of the car and wing mirrors disrupt the air passing over the front windows before crashing back into the rears.

You can mitigate it somewhat by opening another window, which alleviates some of the pressure and changes the resonance. Meanwhile, going faster will generally just make the buffeting louder and more consistent, but really keep your foot in and you should be able to reach a point where it smooths out and dies down – though this probably isn’t feasible away from the autobahn…



Things that don’t compare with that noise:

  • machine guns
  • sonic booms
  • atom bombs
  • volcanoes erupting
  • worlds colliding
05/20/2018 - 07:48 |
132 | 0

In reply to by Anonymous (not verified)

what can compare:

A Fart can Honda revving

05/20/2018 - 09:18 |
86 | 2
05/20/2018 - 08:24 |
62 | 2
Ali Mahfooz

Ayy! Darren Cassey is back again! 💪😎

05/20/2018 - 08:34 |
8 | 2

Me: opening window
Friend: don’t
Me: opens window whomp, whomp, whomp

Option A: close window and accept embarrasment
Option B: open all windows fully

05/20/2018 - 09:13 |
48 | 0

In reply to by CS55

B, has to be B

05/20/2018 - 10:01 |
16 | 0
05/20/2018 - 09:38 |
70 | 0
Luke ZS 96

In reply to by Anonymous (not verified)

Comment of the week

05/21/2018 - 07:18 |
2 | 0

Thank you! Ever since I sold my 2005 Explorer and moved to the 2018 Camry, I was wondering what that noise was if something was

05/20/2018 - 10:56 |
0 | 0

“[…]waves of pressure, which your ears interpret as sound.”

Dude, the sound is annoying. Can you close the window? - No! It’s not a sound, it’s waves of pressure. Leave my Helmholtz Resonance alone!

05/20/2018 - 11:19 |
8 | 0

Technically a sound consists of waves of pressures too ^^”

05/24/2018 - 14:12 |
0 | 0

Interesting, thanks a lot!

05/20/2018 - 11:52 |
2 | 0
Pierce Tolar

That’s why long doors are best

05/20/2018 - 13:16 |
0 | 0

You mean the chopper than lands on the roof of my car everytime I open the windows?

05/20/2018 - 19:32 |
2 | 0


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