Once an anemometer shows signs of dragging, how often will it go into the vibratory mode? 30% of the time in 5-10m/s wind? 70%?

[Julia Austin]

Q: Once an anemometer shows signs of dragging, how often will it go into the vibratory mode? 30% of the time in 5-10m/s wind? 70%?

A: An anemometer susceptible to the vibratory mode will tend to switch into its normal mode at higher wind speeds (above 10 m/s) and at very low wind speeds (below 5 m/s). In the 5-10 m/s range it will vary by sensor and its environment. In answer to this specific question, we don't have a basis by which to identify a typical percentage. We estimate that 20-30% of all sensors manufactured after 2006 are affected by this issue.