Estimate the turbulence intensity Iu, at a height of 33 ft for wind flowing over an open terrain, if the mean hourly wind speeds were recorded in mph as follows: 20.0, 24.5, 30.3, 32.1, 33.2 at 10 ft, 20 ft, 30 ft, 40 ft and 50 ft elevations from ground, respectively. Estimate the length scale of turbulence ( Lu x ) at a height of 33 ft.