Phase difference for Teeside Wind Farm

 Looking along the lines of turbines from Hartlepool South Pier, I realised that the turbines were not in phase. Some had blades at the top whilst some were pointing at 10 degrees. However, this amount of phase was not fixed. As I watched, they came in and out of phase. If they had maintained the same "out of phase" we could have said that they were coherent -  a fixed phase relationship.

The next day we went to North Gare and I was able to time some of the turbines. The time periods were so close that I had to time 5 revolutions to get the differences. Three different times for 5T were 35.20s, 34.67s and 40.54s. The time periods are therefore 7.04s, 6.93s and 8.10s. The differences might be due to nuances in the wind speed in different parts of the array,