Question

The time-step size in explicit schemes depends upon _____________

(a) Grid size

(b) Number of iterations

(c) Total time interval

(d) Given mathematical equation

I had been asked this question by my college professor while I was bunking the class.

The origin of the question is Explicit and Implicit Finite Difference Methods topic in chapter Finite Difference Methods of Computational Fluid Dynamics

Answer 1

The correct option is (a) Grid size

The explanation is: There is a limit posed to time-step size in explicit schemes. This limit depends on the grid size chosen. Once, the grid size is chosen, from the formula given by stability criterion, the maximum possible time-step size can be calculated.