|June 4, 2010, 08:07||
integral length scale and cross-correlation (with openfoam data, LES pipe flow)
Join Date: Nov 2009
Posts: 12Rep Power: 8
i want to calculate the integral length scale of a pipe flow in matlab.
the pipe flow (LES) is calculated with openfoam-1.6 .
I have read out the velocity components (cell center) of 1000 cells in a preview-folder at a one definite time-step.
Now I have to calculate the cross-correlation function (in x-direction):
1. step: i subtract the mean velocity from the axial-velocity-component in order
to obtain the fluctuating velocity u'
2. step: i calculate the cross-correlation as:
ufluct is the same as u' and ucross should be my cross-correlation coefficient?!
but my problem is, my code does not calculate the time-averaged cross-correlation-coefficient because i don't know wich kind of data i have to time-averaged.
i have read some books about it (Pope, Wilcox, Hinze and Lumley ...) but i can't implement their ideas in matlab.
it would be great if somebody has an idea or could explain me how to calculate the integral length scale correctly!