Computation of auto-correlation coefficient without energ spectrum and Fourier trans.
 

Hi all.

I am sorry if this a repeat post. But I am confused about some things. Consider that I have a 2D domain with 10x20 (x and y respectively) cells. I want to calculate the auto-correlation coefficients (f(x) and f(y)) of velocity in the domain which reduces from 1 to zero with distance. The flow is unsteady. The definition mentions separation distance r (when r=x it is longitudinal and when r=y it is lateral in my case). What is the distance r? Given that I have the velocities of all the 200 cells in the domain, how do I calculate f(x) and f(y) to be plotted as a function of x and y?

Any help is appreciated.