Question

The grid size and time-step size of the DNS method depends upon the _____________

(a) Schmidt number

(b) Peclet number

(c) Nusselt number

(d) Reynolds number

The question was asked by my college professor while I was bunking the class.

Asked question is from Direct Numerical Solution for Turbulent Models in division Turbulence Modelling of Computational Fluid Dynamics

Answer 1

Right choice is (d) Reynolds number

Best explanation: The grid size and time-step size of the DNS method is based on the largest and the smallest length and time scales of eddies in a turbulent flow. This, in turn, depends on the Reynolds number of the flow. So, Reynolds number decides the grid size and time-step size here.