Question

Substantial derivative applies to ____________

(a) Both stationary and moving models

(b) Only moving models

(c) Only stationary models

(d) Neither stationary nor moving models

I had been asked this question at a job interview.

The query is from Governing Equations topic in portion Governing Equations of Fluid Dynamics of Computational Fluid Dynamics

Answer 1

Correct answer is (b) Only moving models

To elaborate: Substantial derivatives arise as the coordinates move and they vary with time. So, they are applicable only to moving models.