Whining Sound at Highway Speeds-Normal or Sound of Major Issue?

Hi All, I recently purchased a 2012 Prius with 112k miles. At highway speeds, there is a friction-like/whining sound that I believe is coming from the driver’s side engine compartment area. This is my first hybrid, so I’m not sure if the sounds is completely normal, a major issue, or something in between.

Sound details
· Recording of sound can be found at:
· Occasionally intermittent (pulsing) whining/friction-like sound is noticed at highway speeds (60+ mph)
· Sound is like a taxiing jet
· Sound disappears when car moved to neutral (meaning not aerodynamic, tire, or suspension related)
· Sound occurs when giving it gas/coasting, but is louder when braking or downshifting to “B”
· Unrelated to AC being used
· volume is less than radio at normal volume
· Appears to come from driver’s side engine compartment area.

Any advice on if this is normal or if you have theory on what may be the issue would be greatly appreciated! At first I thought it was “coil whine” or the inverter, but now I’m not so sure.