Question

What is the main disadvantage of explicit schemes in a time-dependent problem?

(a) Marching solution

(b) Simultaneous equations

(c) Small time-step size

(d) Small grid size

I got this question by my college director while I was bunking the class.

Question is from Explicit and Implicit Finite Difference Methods in section Finite Difference Methods of Computational Fluid Dynamics

Answer 1

Right choice is (c) Small time-step size

Explanation: Explicit time-based schemes have a limited time-step size. Big time steps cannot be used. So, the total time of computation required to solve the system is very large when compared to the implicit schemes.