Question: What are one of the ways to calculate noise accurately?

Michael Carley answered on 10 Jun 2016:

There are various ways, but they are all based on working out the noise from different parts of a system and combining them to see how they constructively or destructively interfere. Usually, the noise from each part depends on the aerodynamics of the problem, for example, the flow around an undercarriage, which is a lot of what you hear from an aeroplane coming in to land.