[arjun]

Originally Posted by Kinnikuman

Sorry, still I couldn't get it. So how can we categorize sound induced by flow?

More important than the classification is how do you simulate it.

As you can see from Fluent theory guide, the direct method is capable of simulating the sound. They resort to FWH types of model when direct method can be very expensive to do. In this case Lighthill, FWH provide a reasonable alternative to direct method.

Note that if you are willing to take the expense then the direct method will calculate the far field sound too as pointed out by LuckyTran (you do not need FWH).

Now coming to near field, if you are able to mesh the region and are able to solve the compressible Navier Stokes then you can calculate the near field sound.


As far as sound in solid goes, the first requirement is the solid to be influenced by the flow (That is FSI). When you solve the solid stress equations due to pressure load, you could also track the sound waves through the solids. In the cases where displacement is quite small I am sure someone has come up with simplifications to the equations to track just the sound. But still it is FSI. One need to solve for something in solids due to pressure and friction forces from outside.