Question

Which of these methods is used in the compressible flows to find the densities at the faces?

(a) Central difference

(b) Upwind difference

(c) Rhie-chow interpolation

(d) Weighted average

I have been asked this question during an internship interview.

My doubt stems from Compressible Flows in section Incompressible Flows & Compressible Flows of Computational Fluid Dynamics

Answer 1

Correct choice is (b) Upwind difference

The explanation: The central difference scheme (or linear interpolation profile) produces oscillations at high speeds. So, a bounded upwind first or higher-order equation is used to get the density values at the interfaces.