Question

Which of these methods which are used for time advance discretization in DNS needs more computation per time step?

(a) Adams-Bashforth

(b) Runge-Kutta method

(c) Leapfrog

(d) Newton Raphson method

This question was posed to me during an interview.

Query is from Direct Numerical Solution for Turbulent Models topic in section Turbulence Modelling of Computational Fluid Dynamics

Answer 1

Correct answer is (b) Runge-Kutta method

Explanation: Runge-Kutta method is generally used to advance in time in the DNS method. They need more computation time per unit step. In spite of this disadvantage, they are preferred because of their accuracy.