Must a diesel truck engine be built to make a deafening noise (when pulling out from a stopped position)?Is it necessary for hand dryers in airport and other bathrooms to make the sound of a jet engine taking off ??Is there an alternative way to build machinery that reduces overbearing noise?
It all boils down to cost and function. If you have the money you can make just about quiet.
accoustics is a specialize field in mechanical engineering. u can start thinking about it......... all mechaneries have to be as quiet as possible and submarine has to be totally silent to avoid detection. machineries are noisey because human has no way of finding a way to reduce their nosie yet.....
Moving air creates a sound. There is no way to avoid this unless you trap the air, which then removes the purpose for hand dryers. Friction against parts also has a sound. Good materials, lots of lubricant, and a good/accurate design can reduce the sound. But it's almost like undertaking a separate engineering project in itself, most can't be bothered.
