[cpp_frog]

It is easier to study from a theoretical point of view (easier that the heat or the wave equation: [1], Ch. 2), and it's easier to implement a solving method. When you are learning the finite element method, this is one of the first examples that people use to test if they got the right implementation.

Now, I wonder if the author regards it important in his particular area (aerospace engineering), I'm new to the field so I don't see how. Right now I'm reading a book [0] on models to solve problems concerning aerospace applications and they mostly use a simplified form of the Navier-Stokes equations together with some elasticity assumptions.

[0] Fluid Structure Interacion, Morand-Ohayon.

[1] Partial Differential Equations, Evans.

[leephillips]

If you take the divergence of the incompressible Navier-Stokes equations you get a Poisson equation for the pressure, with a function of velocity on the RHS. So it’s important in fluid dynamics.