Serge_saati mentions a test that is very good.......remove the serpentine belt and see if the problem is still there.
NOTE....don't run the motor for more than a minute.....as you will have NOT coolant circulation.
Now.....if the noise is not there.....then you know that it is something on the serpentine belt line.......Alternator, water pump, power steering, tensioner pulley bearing......idler pulley bearing.
On my '96, I changed the power steering pump.......and the noise turned out to be the idler pulley bearing.
The idler pulley is right in between the alternator, power steering pump and the water pump.
I was SURE that it was the power steering pump......only made the noise above a certain RPM......not at idle......and I could not detect it by turning things by hand.
Years later.....I got a very similar noise......and it was the bearing on the tensioner pulley......I could tell by turning the pulley by hand......felt normal at first....but when I wiggled it and tried again.....I could clearly feel the problem.