I recently found the following image showing the different sources of noise in vehicles. I notice that Aerodynamics is actually quite a big part of vehicle noise, as shown below by the blue line:
I can imagine this is partly because of the flow going over the car. However, I think a part of this noise also comes from separating flows (for example at the rear window).
I was wondering if it is possible to reduce the aerodynamic noise of vehicles by applying separation control.
As such, I'm wondering:
How much noise does a separating flow generate?
I'm guessing this highly specific to the local geometry and velocity, but I would already be very happy with some examples.