Question

What is the problem in modelling flows with high Reynolds number?

(a) A mixture of viscous and inviscid flow regions

(b) A mixture of subsonic and supersonic flow regions

(c) A mixture of elliptic and parabolic flows

(d) A mixture of elliptic and hyperbolic flows

The question was asked in an international level competition.

Asked question is from Mathematical Behaviour of PDE in portion Mathematical Behaviour of Partial Differential Equations of Computational Fluid Dynamics

Answer 1

The correct option is (a) A mixture of viscous and inviscid flow regions

The best explanation: At high Reynolds numbers, the viscous regions are very thin. The part of the flow where the boundary conditions are specified behaves different (inviscid) from the part near the body.