Does it do it in neutral when you rev the engine up... if so it's the Power Steering pump...
A whinig or howling sound coming from a cars wheels means that a wheel bearing is bad and should be replaced.
possibly your wheel bearing is on its way out
electrical interference
not enough oil usually
it's the air intake taking more air and the belts moving faster
whining
the wineing is probably the fuel injecters because that is what was wrong with my dads truck.
A worn out clutch release bearing would cause a whining sound when you put your foot on the clutch.
Doppler effect
What kind of howling? Or is it a whining? Where does it sound like it's coming from.
Your child in the backseat.
the alternating areas of quickly moving high and low pressure