Wind buffeting in cabin

[AZjeff]

What is with the throbbing buffeting you get when you drive with one window down or the sunroof open? I don't remember this happening in any vehicle I owned or rode in up through at least the 90s models. Not sure when it started but the last few newer vehicles we've owned have all done it. Yeah, crack another window and it stops but it sure is annoying. Aerodynamics?

 

[Kuato]

Exactly...modern aerodynamics - although I did notice this in a vehicle back in the 80s.

mumble mumble resonant frequency mumble mumble.

 

[Oro_O]

This isn't a "modern" thing but has always been around. It's called Helmholtz resonance.

The airflow over the single opening acts just like blowing across the top of an open glass bottle. The wind passing will alternately pressurize the interior air, then see that pressure drop as some leaks or forces back out as edge vortices create low pressure areas.

I have acute hearing and sensitive ears so this is painful to me. Theoretically, increased aerodynamics should reduce it - the idea of a more stable boundary layer creates less drag. But once you pop open the window, it won't matter much.

 

[edwardh1]

my highlander does it, no other car ever did

 

[AZjeff]

"Resonant frequency" was what I was trying to think of, thanks. More airtight cabins allow the effect? The RAV4 does it, the previous Jeep GC did it, a rental Altima did it, a Hyundai a sedan we rode in did it. The last car we owned, a Solara, didn't do it. Interesting but annoying.

 

[Andrew1972]

Beyond aerodynamics vehicles likely leaked like sieves...

 

[OneEyeJack]

On our company Prius this problem is painful when driving down the freeway with one rear window open about half way.

 

[DriveHard]

just crack another window...problem solved.

 

[IndyIan]

Originally Posted By: Or

I have acute hearing and sensitive ears so this is painful to me. Theoretically, increased aerodynamics should reduce it - the idea of a more stable boundary layer creates less drag. But once you pop open the window, it won't matter much.

I think its the opposite, turbulent air won't set up a resonance as effectively. I assume this is why the windbreaker bar pops up at the front of a sunroof when it opens. On the Focus its spring loaded and if I pull it down with my hand, resonance starts up right away.
The kids figured out on the CRV that if they open the rear windows about half way down, it creates a buffeting like there's a helicopter taking off in the car... Almost to the point of worrying about the shaking the rest of the glass out.

 

[AZjeff]

Originally Posted By: DriveHard
just crack another window...problem solved.


Thanks I'll try that! Wait, didn't I said that in the OP? Easily fixed but still annoying. The RAV sunroof doesn't add much noise but it really pulses, having to crack a window to stop the pulsing is much louder.

 

[Pop_Rivit]

I've had a number of vehicles that have done that-especially when vehicles started to become more aerodynamic. I had a mid-90's pickup that, if the drivers window was open and the wind direction was just right, felt and sounded like it had a flat tire.

I suppose those cheesy plastic air deflectors might help, but it never bothered me enough to worry about it. I simply open another window and the problem is solved.

 

[HerrStig]

My '67 bug did it.

 

[dishdude]

Remember how doors used to tuck in under the A pillar? There would also be a rain gutter running up the A pillar that would baffle the wind.

Cars starting in the late 80s/early 90s started having the frame wrap around over the A pillar eliminating this buffer.

Not sure if that makes sense or not but it seems to.

 

[Rand]

every car I've had since 2009 has done this.

I just lower both windows on the same side and it will stop the resonance. Both back windows just about blows out my eardrums at 40mph and halfway down.

So I do the one front window about 2in and then the back window 3-4" on same side.

 

[Nick1994]

Surprisingly my Camry doesn't do this.

My mom had a 2003 Ford Focus Wagon and it was really bad with it.

 

[Rand]

Originally Posted By: dishdude
Remember how doors used to tuck in under the A pillar? There would also be a rain gutter running up the A pillar that would baffle the wind.

Cars starting in the late 80s/early 90s started having the frame wrap around over the A pillar eliminating this buffer.

Not sure if that makes sense or not but it seems to.

That seems likely to me.. how cars are rounded off with no drip channels etc.

I can open the sunroof, either front window solo..

but not just the back windows 1 or 2.

the 2013 outback is even worse than my 2015 forester.

 

[Kuato]

Originally Posted By: dishdude
Remember how doors used to tuck in under the A pillar? There would also be a rain gutter running up the A pillar that would baffle the wind.

Cars starting in the late 80s/early 90s started having the frame wrap around over the A pillar eliminating this buffer.

Not sure if that makes sense or not but it seems to.

That's a really good observation.

I tend to think that the reverberation has nowhere to go, until you open another window to let it out. There is probably some high level waveform science to describe it....

 

[AZjeff]

Originally Posted By: HerrStig
My '67 bug did it.


Never would have guessed that!

I'll bet the earlier comment that older cars weren't very airtight has something to do with the phenom, and that a bug would do it. They had the rep that they'd float.

 

[Nick1994]

Originally Posted By: AZjeff
Originally Posted By: HerrStig
My '67 bug did it.


Never would have guessed that!

I'll bet the earlier comment that older cars weren't very airtight has something to do with the phenom, and that a bug would do it. They had the rep that they'd float.
I put about 2,000 miles a year on the 1970 Beetle, it doesn't do the buffeting but it also doesn't have the wing windows, it has 1 piece glass windows instead so maybe that has something to do with it.