Question

Which of these statements best defines local derivative?

(a) Time rate of change

(b) Spatial rate of change

(c) Time rate of change of a moving point

(d) Time rate of change at a fixed point

This question was posed to me in an interview for job.

My enquiry is from Governing Equations in section Governing Equations of Fluid Dynamics of Computational Fluid Dynamics

Answer 1

The correct choice is (d) Time rate of change at a fixed point

Best explanation: Local derivative is the term \(\frac{\partial}{\partial t}\) of a property. This defines the time rate of change of a property at a particular point with the assumption that the point is fixed.