[aerohead]

As I understand it,acoustics as a branch of physics which deals with a sound pressure wave and it's interactions with it's environment.
Aerodynamics,as concerns us,is the reduction of the pressure differential between the forward stagnation point of a vehicle,and the base pressure of the vehicles turbulent wake.
The drag can only be mitigated by reducing or eliminating the flow separation responsible for the creation of the wake of which a symptom is the resonant frequency we detect.
The only prima facie evidence we possess for effective wake reduction is the empirical data from aerodynamic boat tail research.
Once the wake is eliminated,so goes the 'noise' of the wake.