Question

Supersonic viscous problems _________

(a) are always circular

(b) cannot be parabolic

(c) are parabolic

(d) can be parabolized

I got this question during an interview.

This intriguing question originated from Mathematical Behaviour of PDE in section Mathematical Behaviour of Partial Differential Equations of Computational Fluid Dynamics

Answer 1

The correct choice is (d) can be parabolized

To elaborate: Supersonic viscous problems are governed by Navier-Stokes equations. Some assumptions made in this Navier-Stokes equations will give parabolic equations called Parabolized Navier Stokes equations.