I know that transonic aerodynamic buffet is caused by the separated turbulent boundary layer striking the airframe (horizontal stabilizer, wings, fuselage) with considerable force causing a high amplitude vibration, which physically shakes the whole aircraft. And during a buffet, a shockwave will be apparently moving back and forth just like in the video link I provided below:
Since the shockwave is usually stationary on the airfoil, then why it starts suddenly oscillating once we enter a buffet boundary? Any ideas?
