Physics at its finest
"It sounds like a helicopter is landing on my car!!" Is the call we took not too long ago. We have had a few customers come in from time to time and describe a horrendous noise, especially with their back windows cracked open. The reasoning behind this noise is really just simple physics: f=(c/2n)√(S/L'V), yep, the Helmoltz equation named after this guy Hermann Von Helmholtz.
I told ya......Simple. Before you say, what the heck is this grease monkey talking about and think I'm crazy, I have a better answer for you. We call it Wind Throb. Basically, most vehicles now are very aerodynamic to save fuel consumption. The air flowing around your vehicle at a fast rate gets forced through the open window and creates that drumming or throbbing noise. This is almost always normal. It is usually described as the same thing as blowing over the top of your beer bottle. Some of the air flows out and some flows into the bottle creating that beautiful sound. Don't try this while driving, of course. Or for you music lovers out there, this is how an acoustic guitar works! So Jam out and dedicate a song for Hermann as I bet he was the type of guy who likes good music!
Enjoy your day!
